Engine, 0-60mph and gearbox
The entry-level diesel, the 148bhp 318d, has good mid-range flexibility so it never feels slow, but if your budget can cover it, we recommend going for our favourite 320d. Compared to the 318d, the 320d’s 187bhp makes it quicker with few downsides. If you desire a diesel with the ability to worry hot hatches, though, there’s the 330d. Its six-cylinder diesel engine offers rapid acceleration — 0-62mph is dealt with in just 5.5sec.
If petrol is your cup of fossil fuel, the 181bhp 2.0-litre 320i is a great place to start. It's perky enough for most situations, including motorway cruising, but it does need to be revved hard if overtaking on a country road. If you think you'll need more zip then head for the more powerful 254bhp 2.0-litre engine of the 330i. It still needs revs to deliver its best, but cracks off 0-62mph in a sprightly 5.8sec. If you like the idea of a hybrid, the 330e offers that kind of pace, too, but with improved low-end response courtesy of its supplementary electric motor. It also offers an official electric-only range of up to 41 miles on a full battery.
Suspension and ride comfort
There are various suspension options on the 3 Series, and even the standard suspension (with 18in alloy wheels and optional run-flat tyres) is set up more for poise and control than ultimate comfort. It’s very well controlled, so it won’t bounce you out of your seat over heavily undulating roads like the C-Class can, but you always feel more of bumps as they pass beneath the car than you do in the A4.
M Sport models, on their stiffer M Sport suspension and optional 19in wheels, are even better controlled. However, impacts over sharp road imperfections are more pronounced, so be warned: sportiness really does take a higher priority than comfort.
The optional adaptive suspension is available to alleviate this, but is pricey. It's part of the M Sport Plus Package and allows you to stiffen or soften the ride at the touch of the button. Select Comfort mode and the 3 Series is calmer around town than in either of the other tunes above, and really quite smooth on A-roads and motorways. It's still not a patch on the Audi A4 if ride comfort is your top priority, though.
The 3 Series is undoubtedly one of the sportiest executive saloons on the market, alongside the Alfa Romeo Giulia and Jaguar XE. And in terms of outright ability, it's the BMW that reigns supreme, thanks to its class-leading body control and grip through corners.
Versions equipped with M Sport suspension possess the best cornering skills. Those equipped with standard suspension or Adaptive M Suspension are still very good indeed, with a fluidity to their body movements that’s both predictable and pleasing. The 3 Series is a car that inspires confidence, so you’ll enjoy chucking it down you favourite back road.
The steering is another strong point of the 3 Series. It's not quite as measured or full of feedback as the XE's, being instead quicker and more reactive, like the Giulia's. But it ensures you always know how much grip is available, and once you've acclimatised to its immediate response, you find yourself placing the car's nose expertly.
Noise and vibration
Wind noise is very well contained at motorway speeds, but road noise (on the selection of larger wheels with run-flat tyres we’ve tried so far) is slightly more pronounced than in smaller-wheeled versions of the A4. Suspension noise – again, probably not helped by the stiff sidewalls of the run-flat tyres – is also noticeable over bumps.
The six-cylinder engines sound sweet while the four-cylinder engines have a gruffer but acceptable note. Still, the 320d's engine is pretty muted compared with the C220d's, but the A4 40 TDI is even quieter and less prone to sending vibrations through the pedals at a standstill.
Speaking of pedals, the one for the brakes doesn't have much resistance at the top of its travel, making it easy to unwittingly brake too hard. The 330e hybrid’s brakes are the worst affected, because they have to deal with recouping energy for the battery as well, but on the plus side, you get no engine noise when it’s running on electric power alone.