993RS

is not only the increase in maximum horsepower, but also the improvement in the torque curve which really improves driveability. In the old days, the early 911's with their smaller displacemnt had a very peaky torque curve, and consequently you had to go above 5000 revs for action. Chip tuning and the 3.8L upgrade can raise the curve throughout. For example: Originally my 993 showed 242 max hp at 5130 revs at the wheels. After upgrading it to RS specs and chip tuning, it showed 261 max hp at 4850 revs at the wheels. Not so much you will say, but if you look at the torque curve (sorry, I'll have to give the figures in Newton meters... but it shows the relative increase anyway:

3000 rpm original: 260 Nm, RS: 300 Nm
3500 rpm original: 262 Nm, RS: 350 Nm
4000 rpm original: 280 Nm, RS: 360 Nm
5000 rpm original: 330 Nm, RS: 370 Nm
6000 rpm original: 320 Nm, RS: 350 Nm
6500 rpm original: 275 Nm, RS: 330 Nm
7000 rpm original: n/a RS: 300 Nm

So a much better torque curve, big increase at lower revs, and I can rev about 500 rpm more. With the G50/21 gearbox quite a difference!

H20NOO

Excellent points! After all, torque = thrust (acceleration).