Originally Posted by /Angelo350Z/

I never bothered to look into these details because theoretically, what one loses in power, one gains in traction and aesthetics. It depends on the rotational weight of your wheels and tires. All negligible IMO unless you're competing. If you do compete, you don't use your 20" wheels, do you? For what it's worth, I dyno'd my old 350Z on the OEM 18" wheels and tires first, then installed 19" TE37s with 255/285 tires. The numbers were identical.