BMW 4 series VS BMW Alpina B4

One of the main things that sets a BMW sedan or sedan-based coupe apart is that they're good everywhere, except perhaps in quicksand. 

As the platform has matured and BMW's persistence with run-flat tyres has yielded improvements in tyre construction, the 3/4 Series platform (and many others - the internal name for the platform is CLAR) has once again become the benchmark for ride and handling.

For some people reading this, that's a lot of blah blah blah but the main point is, it's a terrific thing to drive whether you're dawdling along in traffic, dealing with traffic calming or bombing down your favourite deserted road.

The Bridgestone tyres on the 420i aren't as ultimately grippy and sticky as the alternative rubber on the 430i but they work well in town and are quiet on the 80km/h roads so prevalent in Sydney. 

The steering is absolutely lovely, providing just the right weight at any given speed and throwing in the road feel to inspire confidence.

Ride around town is compliant but with the whiff of fun if you decide to push things outside of the city. 

Its capabilities are still more than worthwhile day-to-day, however, because the way it handles the need to duck in and out of spaces in traffic is extremely handy.

The 2.0-litre four-cylinder is as smooth as rival Audi's. It doesn't sound like much (with a few vestigial pops in Sport mode) but it's certainly got the power to get you out of sticky situations and a transmission that's willing to play ball, whether in Sport or Normal.

Without the adaptive suspension of its 430i and M 440i brethren, this is a very smooth, easygoing sports coupe, with just enough sportiness to keep you interested, if you're that way inclined.

One of the key differences between the B4 and M4 is the ride. While the M4 can crash over bumps and generally be a little hard to live with, the crew in Buchloe have gone after a much more plush ride. And in that they have succeeded because the B4 S is a mighty fine cruiser. Bumps are dismissed with a haughty disdain, even Sport + silliness doesn't completely write-off ride quality.

Very impressive too, is the steering. While still not at Lotus Elise levels of feel (few cars are), the Alpina tweaks connect the your palms to the road with more clarity than what you'll find in the 440i or M4. Where the M4 particularly adds too much weight, the 440i is a bit more circumspect in that regard.

And then we come to the engine. The B58 six is a belter, better even than the N55 that preceded it. It's still a 3.0-litre straight six but is part of BMW's modular engine family that starts with a 1.5-litre triple in the Mini and 1 Series. The Alpina-spec turbos are noisier, the Akrapovic exhaust lighter and also noisier. It doesn't have the all-out crackle and pop of an Audi or Merc (perish the thought), but when you're on it, the B4 means business. The 660Nm of torque, available over a wide rev range, delivers a steel fist wrapped in a velvet glove and bubble wrap - the speed builds rapidly but smoothly. 

The approach to the chassis tune seems to be based on the driving talents of mere mortals on normal roads, which is kind of like the 440i. It's terrific fun to drive hard but it's very forgiving and patient. The great thing about it is that you wouldn't think twice about jumping in it for the long haul, so comfortable and quiet is the cabin. The M4 will leave it for dead on a winding road, but that's perfectly fine.

One irritant is the replacement of the admittedly cheap BMW gearshift paddles with weirdly non-tactile buttons. They're not particularly easy to use and, probably worse for a sporty car, unsatisfying. It's an odd detail with which to go off the reservation. Cheeringly, the eight-speed ZF is its usual perfect self, so you don't have to worry too much about manual mode or go old school and use the shifter.