The massive upswing in the successful application of turbocharging in other marques paved the way for BMW to make use of this form of induction as a viable solution to a rather big problem that BMW faced. Basically, turbocharging - and consumers' willing acceptance thereof presently - rescued a situation that BMW otherwise would not have been able to solve going the naturally aspirated route.

Don't think for a minute that BMW have singlehandedly revolutionised the way that turbocharging is employed in the modern petrol engine. The solution is nothing extraordinary from an engineering perspective; it's simply two light pressure turbos bolted to an already powerful 3 litre six cylinder engine. Yes, but what about the lack of turbo lag you'll ask? I'll counter that by saying that the low inertia turbo installation is profiled for low-down boost and seamless power delivery but is hardly a paragon of top end power delivery for an engine of such specification. It could have been much, much more, at the expense of that famed straight six linear power delivery. Light pressure turbocharging has been around for almost 8 years in its current and successful state.

BMW faced a marketing dilemma and turbocharging was the obvious solution.
The problem of course (for all of my detractors who are currently going "who is this d!@k&e#d?" ) is the Newton metre per litre output of engines that ingest air at ambient atmospheric pressure. As such, they lack the volumetric efficiency to consistently produce more than 105 Nm per litre without employing some hectically sophisticated engine management systems (e.g. M5's S85 system).

So what were BMW to do? Increase the displacement of the straight six? Not an option apparently as this would detract from the optimal bore and stroke characteristics of the sixer and make it longer and heavier as a consequence. Sure there's the option of a V8 but surely that's less efficient than a turbo'd six? Bingo. Welcome to the turbocharged era for mainstream BMWs. Most definitely unchartered territory for BMW, no question. Turbo'd 2002s don't count...

But back to the matter at hand (after all of that) yes, I most certainly believe that the 335i (especially in Sedan and Touring guises) is a perfect opponent to the more expensive S4 range. After all, I did say it in this (E90 335i and 335d from september 2006)thread

BMW has, quite suddenly, moved the goal posts again. This is one of the reasons that they're so successful and profitable.