I'm with brad on this one. Don't get me wrong though, I'm all for further development on the internal combustion engine, but there is still the limitations of fuel. There is a finite amount of fuel stored in any specific amount of gasoline. I don't have the exact equations on me, but any N/A engine can only make so much power before it's limitations are pushed by the amount of gasoline entering the combustion chambers.
Secondly - the gasoline engine is on it's way out. This cannot be denied. Fifty years from now, someone that wants to get fuel for their 1998 skyline will need to buy gasoline at some place like a hobby shop, probably at ~$15 per gallon. Like many other sources for energy, something more efficient has been found (ie. electric), and the majority of attention will be forced towards that. You don't see people riding around on buggys that are pulled by horses on drugs. It just isn't practical - not to mention people would frown at the poop in the streets. Likewise, the 'poop' in the air will only be tolerated for so much longer.
Now, I know that I've gone completely OT on this, but think about the S2000 and E46 M3. If I were to purchase either of these, and wanted more power like most enthusiasts - how would I do so? There are a couple supercharger kits for the S2000, and no forced induction that I know of for the M3. Both engines are pretty much tuned to their peak for N/A operation. Also, while speaking of these engines, there is the issue of power curves. Here are the three most common scenarios:
1) large displacement
pros: insane amounts of power
cons: power band is somewhat narrow, because the torque curve can't easily be made for both low and high RPM power.
Excessive fuel consumption at all engine speeds
2) small displacement
pros: good fuel efficency, and capable of decent power
cons: engine has to rev it's heart out to start making power. Power band looks like a stalagmite.
3) forced induction
pros: low fuel consumption during cruise, very high amounts of power available on demand
cons: high power not readily avialable at off-idle engine speeds. somewhat lagged.
So in all of these, my choice would be the turbo (I don't care for superchargers). I don't care to chew up tons of gas while just driving around town, but if I want power - the turbo takes a second to spool and power is available around 2500rpm (average application). With a small displacement/high revving engine, Honda B16A for example - I don't really want to rev to 6k just for decent power. That's worse than any case of turbo lag I've heard of.
Those are my opinions, reinforce or criticize.
