BMW 3 Series vs Audi A4: Both Depreciated. Only One Is Right for Your Situation.

Both offer premium quality for less. The costs to run both are higher than the listing suggests.

The F30 BMW 3 Series and the B8/B9 Audi A4 are the two most naturally compared premium used buys at £10,000–£18,000. Depreciation has done its work — you get leather, sat-nav, heated seats, and in many cases a sport suspension at prices that would have bought a mid-spec Ford Focus when new. What the listing doesn't show is the service bill gap between a BMW specialist and an Audi specialist versus what you were paying on your last car. Budget for 40% more per service than you'd spend on a mainstream equivalent. That's still reasonable — but it's a number to have in your head before you buy, not after. This guide focuses on the three things that split buyers at this price point: fault profile, running costs, and which body style offers what. The driving character question has an easy answer — the BMW wins — but for most daily-use buyers that isn't the deciding factor.

The fault comparison: N47 chain versus HPFP and S tronic

The most important BMW fault at this price point is the N47 diesel timing chain — the same engine covered in the BMW 3 Series buying guide. The N47 (2012–2015 F30) places the chain at the rear of the engine; a failure requires removing the engine, and the repair runs to £2,000–£3,500. A metallic rattle on cold start is the symptom. The DVSA record often shows an 'excessive engine noise' advisory before the seller acknowledges the issue. A post-2015 B47 diesel is a different car and is the engine to target. The Audi A4 B8 (2008–2015) has two documented problem areas. The high-pressure fuel pump (HPFP) on the 2.0 TDI can fail and cause rough running, fuel pressure warnings and in severe cases a no-start. Repair is £400–£800 depending on the extent of the failure. The S tronic twin-clutch gearbox (7-speed wet clutch on the B8) is a more robust unit than the Ford Powershift or early Golf DSG, but mechatronic failures still occur — typically after 80,000+ miles and usually signalled by rough or delayed engagement. The DVSA record can show gearbox advisories before this becomes a full failure. The B9 A4 (2015 onwards) addressed most of the B8 issues and is the cleaner used buy at the top of this budget. If you're looking at a B8, run the DVSA history on both the BMW and Audi before deciding.

• BMW N47 (2012–2015): rear timing chain. Failure cost: £2,000–£3,500. Look for 'engine noise' advisory in DVSA record.
• BMW B47 (post-2015): front chain, much improved. This is the engine to target on F30.
• Audi A4 B8 2.0 TDI: HPFP failure risk. Look for 'fuel system' or 'engine management' advisory in DVSA record.
• Audi S tronic B8: 7-speed wet clutch is more durable than Powershift, but check for gearbox advisories on 80,000+ mile cars.
• Audi A4 B9 (2015+): cleaner fault profile. Worth stretching to if your budget reaches £15,000+.

Running cost comparison: where each car wins and loses

Service costs are broadly comparable between a BMW independent specialist and an Audi independent. Where they diverge is brakes — the BMW M Sport's larger assemblies cost noticeably more than SE/Sport, while the Audi S line uses standard-size discs with sports pads. If you're choosing between M Sport BMW and S line Audi, the Audi is cheaper to brake.

• | Category | BMW 320d F30 SE | Audi A4 2.0 TDI B8 SE |
• | Annual service (independent) | £200–£350 | £190–£320 |
• | Full brake replacement (all round) | £500–£900 (M Sport) / £400–£600 (SE) | £450–£700 (S line) |
• | Front tyres (common size) | £90–£130 each | £85–£125 each |
• | 3-year depreciation rate | ~38–42% | ~40–45% |
• | Premium: estate vs saloon | ~£1,000 (Touring) | ~£1,500–£2,000 (Avant) |
• Winner on brakes: Audi (unless buying BMW SE/Sport non-M Sport). Winner on resale: BMW slightly.

BMW for driving, Audi for the Avant: the trim and body style decisions

The BMW 3 Series is genuinely the more rewarding car to drive — the steering is more communicative, the chassis balance is more neutral, and even SE trim in the F30 saloon feels sorted at speed. If how a car drives matters to you, the BMW wins without argument. The Audi A4 Avant (estate) is a different conversation. It offers 505 litres of boot space with the seats up against the BMW F31 Touring's 495 litres — broadly comparable, but the Avant has a longer, lower load area that most families find more useful. The Avant commands a larger premium over the saloon than the Touring does, but it holds that premium better at resale. For a daily driver covering 15,000+ miles a year: post-2015 BMW B47 320d SE or Sport in F31 Touring is a strong recommendation. For families needing maximum practicality and a cleaner fault profile: Audi A4 B9 Avant 2.0 TDI in S line or SE. For either car, confirm the engine generation before you travel. A pre-2015 N47 BMW or a B8 Audi with HPFP advisories and no receipts is a car worth negotiating hard on — or walking away from.