I was watching one of those TV shows about auto's. They had tricked out a rice burner with a bunch of upgrades including larger wheels. I didn't see the beginning where a baseline run on the dyno had been done. But at the end, another dyno run showed a loss in hp. The spokesman actually appeared surprised while the other guy was trying to expain why. Said it was not unusual for the hp to drop as a result of bigger tires and more unsprung weight, but it should result in better track times. I don't think that either of them really expected to see a loss of hp. And it didn't say much for the exhaust and intake mods either. It's true for our trucks as well. If you go to bigger wheels, you lose rear wheel hp unless you do a gear change. But I also like the better handling of the bigger tires and wheels, and of course the looks. So I do it anyway!