Mercedes-AMG A35 vs Audi S3 vs BMW M235i GC: Which sedan has the lowest running costs?

Can you pre-determine your car’s running costs?

When considering a car’s running costs, it’s important to look at it over the full life-cycle. This allows third or fourth owners of older cars to get a clearer picture of possible future expenses, and it helps first owners to determine at what age their cars may become too expensive to run. 

There are certain key points which could give an idea of a car’s general upkeep requirements. This includes the length of the service intervals, the cost of replacement tyres and service- and maintenance parts, and the prices of service parts. Seeing as these three cars are all rather pricey when new, it’s likely that their running costs will be of lesser concern to new-car buyers on account of the extensive maintenance plans standard on all of them. 

For those fortunate buyers, the main concerns would be reduced to depreciation, tyre prices, insurance and fuel thirst. However, second- and third owners might want to know just how fat their wallets really need to be to own such a (by then massively depreciated) high-performance sedan.

 

Let’s meet the contenders

Mercedes-AMG A35 4Matic Sedan (R 890 520)

This is a very new addition to the Mercedes-AMG stable, for two notable reasons. It’s derived from the first A-Class sedan, and it’s the first time for an AMG badge to be applied to any A-Class that doesn’t have a “45” somewhere in its name. It arrived in South Africa midway through 2020, and immediately made a favourable impression, with its balance spread of finely-tuned abilities.

Power is, as with all three of these contenders, sourced from a 2.0-litre 4-cylinder turbo petrol engine, and maxes out at 225 kW and 400 Nm in the AMG. As with the Audi, power is sent into a 7-speed dual-clutch automatic gearbox, before being distributed to the tyres through an on-demand AWD system. Claimed performance is suitably brisk, with a 0 – 100 km/h dash in 4.8 seconds and a governed top speed of 250 km/h. (The latter figure is applicable to all three cars in this trio).

Related: They may be related, but they excel at different tasks. In this review, we compare the Mercedes-AMG A35 Sedan to its CLA 45S sibling. 

 

Audi S3 quattro Sedan (R 782 189)

In spite of being the most elderly in this group, the Audi S3 still carries a lot of street cred, even in the face of its upcoming replacement. It still looks pretty fresh and modern, too, partly due to some well-considered facelifts through its run. Derived from the first-generation A3 sedan, the S3 gets a healthy power boost and all-wheel drive, which turn it into a rather different beast to the rather milquetoast A3 “40 TFSI”.

The S3 sedan posts the most-impressive acceleration figure here, with the 0 – 100 km/h dash dispatched in a claimed 4.6 seconds. This is due to it being the lightest car in this comparison (weighing-in 100 kg lighter than both of the others), and a small power advantage: the S3’s 228 kW is slightly higher than either of the other two’s peak outputs, although the S3's AMG-matching 400 Nm is soundly trounced by the BMW’s 450 Nm.

Related: The top 5 Audi S3 articles on AutoTrader.

 

BMW M235i xDrive Gran Coupe (R 831 164)

Although BMW insists on slotting the “coupé” descriptor into the range-topping M235i xDrive’s name, it’s as much as sedan as it could be. That sloping roofline doesn’t lead to an opening fastback, and its proportions are way too stubby to establish any real coupé credentials. Don’t think of this as a 2 Series coupé with extra doors, then – at its core, this is just a 4-door derivative of the latest, UKL2-platformed (FWD-based) 1 Series hatchback.

It mostly plays along the same rules as its opponents here, with a turbo 2.0-litre petrol engine and AWD, but its transmission is an 8-speed torque-converter-based system instead of a 7-speed dual-clutch unit. Outputs are more than competitive: there’s a Mercedes-matching 225 kW on tap, while the peak torque rises to 450 Nm (the highest in this trio). 

Blame for the slowest acceleration in this group should likely be laid at the door of the M235i’s smoother-shifting gearbox and substantial kerb weight of 1 570 kg (same as the AMG). The 0 – 100 km/h sprint is claimed to need 4.9 seconds, putting it a bit behind the A35 sedan and quite far behind the S3 sedan in accelerative abilities.

Related: In this video review, we compare the Mercedes-AMG A35 Sedan to the BMW M235i GC.

 

Which one has the lowest running costs?

Purchase price and depreciation

The Audi S3 scores an initial victory here, simply because its base price is significantly less expensive than its opponents – almost R 108 000 lower than the A35 sedan, and almost R 50 000 lower than the M235i xDrive. Its consequently lower instalments will cost an Audi S3 buyer about R 1800 less every month than an A35 buyer (and almost R 800 less than an M235i GC’s owner) would have to pay, emphatically turning the statistics in favour of the Audi when buying new.

Seeing as we’re comparing the S3 to very recent arrivals, we had a quick look at its initial depreciation (after one year, and with at most 20 000 km on the odo). Under these conditions, the 2020-vintage S3 sedans on site are actually worth more now than they were when new, carrying a solid 100.7% of their initial value at the time of writing. 

Applying the same criteria to the Mercedes-AMG A35s on site gives an even better showing, because it retains 108.4% of its original value. This means that, if you bought a new A35 sedan last year, you could actually theoretically put it back on the market right now and get back more than you initially paid. The BMW also does quite well in this regard, retaining 103% of its new-car value after a year. 

Please note that these figures are based on the average values of the cars listed here on AutoTrader, and may not adequately reflect the presence (or otherwise) of extra-cost options fitted to these particular cars. It’s also still too early to cast any verdict of either the BMW or AMG’s longer-term resale values, because they’re both still so new on the market. 

However, lesser Audi A3 variants still retain up to 73% of their initial values after 3 years. The other two should be roughly in line with this trend, given the resale performance of other models in their respective ranges.

Instalment calculator

*Calculated according to the AutoTrader Car Finance Calculator, with a 72-month finance agreement, 10% interest rate, 10% deposit, and no residual value. All prices listed in this article were accurate at the time of writing, but may change without prior notice. Prices include carbon tax and VAT, but exclude optional extras and dealer charges.

Mercedes-AMG A35 Sedan

List price: R 890 520

Instalment: R 14 848/month

Audi S3 Sedan

List price: R 782 189

Instalment: R 13 042/month

BMW M235i xDrive Gran Coupe

List Price: R 831 164

Instalment: R 13 828/month

Related: Which Audi A3 trim depreciates the fastest?

 

Fuel efficiency 

Going on official average consumption figures, the Audi S3 scores another win with its considerably lower claimed average of 6.4 ℓ/100 km. The Mercedes-AMG A35 gets closer to this standard, but its claimed average of 7.3 ℓ/100 km is some way off from that of the Audi. Taking up the third place is the BMW M235i xDrive, which posts a claimed average of 7.9 ℓ/100 km.

In real-world conditions, none of them will even get close to these claimed figures, however, as the temptation of unleashing all that power will inevitably lead to (at best) low-teen numbers, if you’re lucky or moderately restrained in your driving style.

Related: Which engines have the best efficiency?

 

Warranties and maintenance plans

We need to note that the Audi’s warranty only runs for one year, but covers an unlimited distance. The BMW and Mercedes-AMG warranties provide coverage for two years, but again with no mileage limit. They all have extensive maintenance plans, though, with identical coverage for 5 years or 100 000 km, largely rendering the warranty duration a moot point anyway. 

Related: What is usually covered under a manufacturer’s warranty?

 

Insurance

All three cars are considered to be high-performance machines, so their insurance premiums are likely to be significant. They are also all considered higher theft- and hijacking risks, leading to further-inflated insurance costs. The Mercedes-AMG will however have the highest insurance premiums of this trio, simply because it will cost the most to replace – that’s its higher sales price coming into play. 

Also remember that insurance premiums will vary, based on the projected mileage to be covered, and where the cars are kept and driven, both in the daytime and overnight. Younger drivers or those with prior accident histories will experience additional penalties, due to their higher collision risk.

Related: Top tips to save on your car insurance.

 

Tyre replacement

Standard tyre prices play a significant part in any running cost evaluation, but it’s not always a given that smaller tyres will be less expensive – if they’re less commonly used, they might be harder to find and more expensive to replace than larger tyres which are in wider use. We’ll ignore the vast array of optional, larger tyres that are available for all three of our contenders, and limit this part of the costing to the various base-trim’s tyre replacement costs.

Both the S3 and M235i roll on 225/40R18 tyres as standard – a size which is very easy to find in the marketplace. “Store-brand” replacements can be had for as little as R1 500 each (excluding fitment and balancing), but since these are high-performance cars, we’d recommend big-brand performance tyres instead, which cost from R2 200 upwards.

The Mercedes-AMG A35 also has 18-inch wheels as standard, but its footprints are slightly wider, thanks to 235/40R18 tyres. Once again, there are many aftermarket replacements available, but comparing the same brand and model of tyre shows that the AMG’s wider tyres are about R 400 more expensive apiece than those of the Audi and BMW. A draw for first place between the Audi and BMW, then, with the Mercedes-AMG slotting into a rather pricier third place.

Related: How long is a tyre supposed to last?

 

Verdict

First-time owners will need to weigh up the advantages of each of these cars individually, to decide which criteria are the most relevant. We need to slot the Mercedes-AMG A35 sedan into last place overall, though, for two reasons. Firstly, its higher purchase price leads to much higher instalments and insurance costs, and secondly, its expensive footwear places it behind the other two in general maintenance costs.

Second place goes to the BMW M235i xDrive GC. It slots between the Audi and AMG in the price ladder, giving it middling instalments (in this company) and insurance costs. This disadvantage is compounded by its rather thirstier drinking habits, which offset its less-expensive tyres, cheaper instalments and less-expensive insurance (compared to the A35) to a large degree.

Which brings us to the oldest contender in this group, which should also be the most affordable to run for the first few years. The Audi S3 Sedan is the lightest on fuel here, has the lowest instalments and insurance premiums, wears the most-affordable tyres, and has wider aftermarket support for long-term owners. 

Just be aware that dual-clutch gearboxes (as found in the Mercedes and the Audi) only have a finite life, and buyers are advised to set aside some extra money over the first 5 years of ownership to cover potential gearbox rebuilds. (This also applies to anyone buying a car with a DCT when it’s a few years old). Or just hope that the gearbox needs attention before their maintenance plans runs out, in which case the manufacturers will foot the (significant) bill...

 

Recommended Next:

Shop for new and used Mercedes-AMG A35 cars for sale here.

Shop for new and used Audi S3 cars for sale here.

Shop for new and used BMW 2 Series Gran Coupe cars for sale here.

Find out how non-AMG A-Class running costs compare to its opponents.