[norMcal]

Since the discussion went a bit off topic already, let me ask this. What is the big deal with the S55 engine over the N55? Sorry for my ignorance, I really have not paid all that much attention the last few years. I used to know everything there is to know about a M3, but since these cars have become so big, I really lost interest.

Just a quick background. I grew up riding in my dad's Bimmers, from 2002' up to e30's. I later continued the tradition owning e30's all the way to e90's (several M3's), but since have gone back to an e46 M3, just because the new models have gotten too big for me. With the introduction of the M2 I am, for the first time in years, interested again in a new BMW.

That being said, in the past, M engines clearly stood apart from non M with the individual throttle bodies and where always better "breathing" and higher reeving and true race bred engines. So what is the big deal about the S55, other than the obvious hp jump? Is it lighter, or does it have much better throttle response? Because on paper, they are both turbo engines and we all know getting more hp from a turbo is just a matter of tuning and adding some boost. I mean, can't the N55 easily be tuned to M4 type numbers? Yes, I understand the S55 could probably be tuned as well, but realistically, how much hp do I need? I'm really not interested in drag racing and on the track you can only get so much hp to the ground anyway. Doesn't the M4 suffer from having almost too much hp and thus has a tendency to spin out?

Looking back at history and the Z3 M for example. Clearly the ones with the S54 engine are much more desirable, so in terms of resale there is a big incentive going for the later model years. Then again, that was going from the POS S52 to the glorious S54. arguably a bigger difference, or is the difference from the N55 to S55 comparable to that?