Originally Posted by dtc100
Many would argue an NA engine (especially the BMW 3.0 I6, or the V8 in M3, or the V10 in M5) is the true form of a finely tuned and balanced engine, not some forced induction engine. The Audi 2.0T is not an NA engine, it is also a 4 banger which lacks the kind of smoothness and balance an I6 has.
In that sense the NA I6 in the 330i is a true state of art engine, not the one you find in a 335i. Unfortunately BMW no longer sells the high power NA I6, the one in the 328i is somewhat detuned, though better than the one in the 325i. Still many would say an NA I6 is a presentation of what the best engine one can build.
Anyone can slap a turbo or super charger on an engine and call it a day, in our case BMW isn't even too good at it given the HPFP issue, but to make the best out of an NA engine takes real talent.
You can of course argue all you want why a forced induction engine can be a true showing of talent, just don't go around tell those who like NA engines that they don't care what is under the hood.
And many would argue that forced induction is the way of the future and that N.A. engines are holdbacks from yesteryear. I agree, the VW/Audi 2.0T is not comparable to a BMW I6 (N.A. or otherwise), but there's a reason it's won awards over and over again (alongside the BMW I6's, I might add). Speaking to your second point about anyone slapping a turbo- or supercharger on an engine, you are right, anyone can do that. But, very few have managed to do so and make the forced induction aspect barely noticeable to most and not noticeable at all to many.
People on websites like this are the exception, not the rule. Ask the "typical" BMW owner what kind of engine is under the hood and I bet very few will know that it's an I6. In fact, I've even seen for sale ads describing the engine as a V6! I drive a BMW, so of course I see them as something special in the mass of blah cars that we have in the U.S., but far too many people in the U.S. are buying the roundel on the hood rather than the machine beneath the skin.