The compression ratio isn't going to make that huge of difference in horsepower. Also - the turbo is working so long as exaust is flowing through, it just needs a certain amount to hit full potential. I know the 924 Turbo was getting "on it" sooner then my NA 944 does. I have not yet driven a 951. I want to at least ride in one. The 924 Turbo I drove has me wanting a turbocharged car - I realy liked the turbo feel.

Compression ratio makes a huge difference to torque though, which is what you feel in the low RPMs.

Also, while the turbo is technically spinning, it isn't necessarily producing boost at low RPM. My guage doesn't register any boost until about 2,800 RPM if I have my foot to the floor in a high gear. Until then, the manifold pressure is atmospheric or less.

As I said, I love my 951 and wouldn't trade it for an S2, but it is less potent below 3,000 RPM than the 2.7 litre 8-valve NA that I had previously.

A higher compression ratio is what makes modern cars so much more powerful than a few decades ago. The original small-block Chevy made something like 165 hp, and probably had 7:1 or 8:1 compression. The same engine design today can pump out 400 hp with 10:1 or 10.5:1.

Fuel technology has allowed engines to run higher compression without detonation.

Old radial airplane engines designed in the 30's run about 6:1, because that was the max before 1930 gasoline would detonate.

As octane ratings have gone up, compression ratios have followed, allowing massive performance increases, in both power and efficiency.

No contest, the 944 Turbo is much faster...

The "S" does have quite a bit more then the normal 944 na, although you have to push it to the upper RPM's to feel the diff...