Alpina B4 S review: the classy BMW M4 alternative

That’s a jazzy BMW. Who tuned it?

Woah, woah, woah! This is NOT a BMW. And this is NOT a tuner car. This is an Alpina – a car manufacturer in its own right, not just a tuner. Well, according to the official German body that ratifies these things.

What does Alpina do then?

Well, using standard BMW models as a foundation, Alpina tries to ‘out-M’ the M Division, but not with shoutier exhausts, wilder paint and lots of carbon fibre.

Rather, Alpina has a tendency to massage the natural attributes of the car, which often results in deliciously refined performance and comfort. Its cars are wonderfully subtle under-the-radar, Q-cars. For people who know, they’re cooler, better and nerdier BMWs. To everyone else, they’re just another BMW.

Interesting. What’s this one then?

The B4 S. The replacement for the B4 and, if you look at the numbers, an M4 rival. But it has a very different character to the M4, as it tries to tempt people out of the M-badged performance 4-Series with its extra speed, smoothness and desirability. It’s a gentleman’s performance car and has been gloriously honed in a direction we very much approve of.

So what have they done to it?

In essence, the B4 S is a heavily-pimped 435i. Alpina takes the three-litre straight six ‘N55’ engine but it’s been recast to allow for a second turbo to be bolted on. The 10 per cent bigger turbos, increase in cooling (20 per cent) and better oil management allow the Alpina to churn out 434bhp and 486lb ft of torque.

That’s marginally more power than an M4 (9bhp) but a noticeable slug more torque (81lb ft). It’s all fed through an eight-speed automatic gearbox rather than the M4’s double-clutcher to either the rear wheels or, for the first time, all four wheels.

Rear-wheel-drive B4s hit 62mph from a standstill in 4.2sec, while four-wheel-drive cars do it in sub-four. Which will keep M4 drivers quiet in the pub.

Any other tweaks?

The chassis remains the same, but the B4 S gets a fresh set of Alpina springs, dampers, anti-roll bars and front camber and toe-in has been dialled in compared to the M4. Noise comes courtesy of a suitably subtle Akrapovic exhaust.

Then, of course, there’s plenty of visual upgrades such as Alpina’s lovely 20-inch trademark wheels, a badged chin spoiler, diddy roof spoiler, Seventies throwback pinstripe livery and classic Alpina green or blue paint. Which goes perfectly with the Werther’s Orignal tan leather with cream piping and all the Alpina emblems and build plates that are scattered around the cabin.

What’s it like?

Understated performance at its best. Where the M4 shouts its go-faster credentials at you through spiky handling, an abrasive exhaust and harsh ride, you serenely surrender to the Alpina’s relaxing but wonderfully accelerated pace.

The engine is smooth and, with that extra torque, happy playing down at the lower end of the rev-range. This, in conjunction with its buttery ZF 8-speed torque converter auto, makes the car a lot more approachable to drive fast than the M4. And it is fast. Elegantly fast thanks to the much-improved ride that irons out our corduroy roads in a way the M4 could only dream of.

This more forgiving suspension set up - plus the fact it weighs 1,690kg - provides better traction around corners. Where the M4 would normally skip over rough surfaces and fight for traction, the Alpina remains planted to allow the now standard Michelin Pilot Sport 4 S tyres to do their thing.

Unfortunately, The B4 S suffers from the same overly weighted steering as the M4 and fails to communicate what’s going on at the front wheels effectively thanks to a strangely overplumped steering wheel.

Can't you alter the weight, though?

Unlike the M4, you can’t manage the violence of the steering, powertrain and suspension in isolation. You have to increase the intensity of your driving experience in one go as the driving modes are clumped together in ‘Comfort’, ‘Sport’ and ‘Sport Plus’.

Comfort suits the Alpina’s relaxed mentality and charm perfectly, and offers you all that performance with added squidginess. But, even though it doesn’t really lend itself to hooliganism, if you want it to, you can put it in maximum attack for a more focused driving experience.

And, with all that torque on offer, it’s quite happy to rip off its tie, unbutton its shirt and do a drifty war dance thanks to a mechanical limited-slip diff now fitted as standard.

Should I buy one?

If you break it down, BMW M and Alpina do very similar things. Each takes a regular 3/4-Series as a base. Each messes with the chassis, engine, bodywork and interior. Each also offers levels of acceleration and performance to keep any speed freak entertained. Yet, you couldn’t have two more different cars. The Alpina is sophisticated and docile in how it pounds your organs with performance. The M4 isn’t.

Starting at £63,000 – with the possibility of that price rising to over £70k as you wilfully tick boxes to make your luxurious understated performance car more wonderfully understated and luxurious (with things like finer leather, subtler paint finishes and a £2,500 touring pack) - the B4’s slightly more expensive than an M4. But see that premium as an entry fee into a very exclusive and discerning members' club of car enthusiasts. One that we'd very much like to be part of.