The biggest news for the 3-Series Coupe is the introduction of the 335i engine, although undoubtedly it will be applied to the sedan and most other BMW series soon. While the name of the car suggests a 3.5-liter V8, in fact its heart is a twin-turbo 3.0-liter straight-6. Codenamed N54, it is a development from the normally aspirated 3.0-liter unit (now updated to an astonishing 272hp and is called N52). This is BMW's first turbocharged petrol engine since the 1980 745i. For a quarter of a century, the company insisted to use only normally aspirated engines in order to deliver the best linearity and throttle response to delight its demanding drivers. Nevertheless, as the technology of turbochargers progressed quickly in recent years, and the market / legislation calls for more efficient engines, turbocharging is once again put on the map of BMW.

The N54 engine employs a pair of small turbochargers to boost a very light pressure - only 0.4 bar. Therefore it produces "only" 34 more horsepower than the updated normally aspirated version, or a total of 306 horsepower at 5800 rpm. However, the small turbos in addition to the most sophisticated piezo direct gasoline injection (faster response than regular solenoid injectors) allows a normally aspirated-like compression ratio of 10.2:1 and a very strong torque curve, with a peak of 295 lbft (up 63 lbft) running continuously from 1300 rpm all the way to 5000 rpm. This made the variable intake manifolds and Valvetronic redundant, therefore discarded. The higher mechanical and thermal stress called for a negative change though: the magnesium outer crankcase is replaced by a conventional aluminum block with cast iron liners. At 190 kilograms the twin-turbo N54 is 28 kg heavier than the magnesium normally aspirated engine. Audi S4's 344hp 4.2-liter V8 is only 5 kilos heavier. Nevertheless, sticking with 6 cylinders allow the BMW engine to return remarkable frugality - 29.7 mpg according to EU combine cycle. Audi manages only 21.2 mpg.

On the road, the 335i engine is a gem. It feels like a large capacity V8 instead of a turbocharged six, thanks to the absence of turbo lag, the astonishing bottom-end tractability and the quick throttle response. You will be difficult to sense that it is actually a turbo engine. Yes, when approaching the 7000 rpm redline it could feel slightly breathless, and at most rev the engine produces a deeper, bassier noise than the normally aspirated version. That's the only indication of its real identity.

While 0-60 mph in 5.2 seconds may not sound too much improvement from 330i, 335i has far superior real world performance due to its strong torque curve. It could be even quicker than an E46 M3 if both drivers are driving at 90 percent effort - think of those 343 horsepower releases at a heady 7900 rpm and only 269 lbft of torque is available at no earlier than 4900 rpm. Combining "junior M3" performance and the frugality and civility of regular 3-series coupes, BMW's decision to return to turbocharging can't more more correct.