If you know a lot about tires and wheels, i need your help in an arguement against my dad. I want to get new wheels and tires. I have 15" hub caps right now. I want to get 17" mr7's and new 215/45/17 Faulken High Perfermance tires. He says it is bad to get different size tires because my car was designed to run a certain way, and this is changing it. That my tire will a) fit in the wheel well for now, but when i go over something like train tracks, the tire will hit the metal and chew up the tire. b) that everything in the engine will be thrown off. That my car was designed to shift at certian rps, and my speed is calculated by rotations, and that everything will be thrown off with new size tires. I tried to tell him that a computer can be changed to recognize the difference, but he said it can't. c) his basic arguement is that the tires won't performe as well and that i am messing with something that is designed to run a certian way. That professionals have tested and found the best way my car runs, and that i am messing with that, and asking for trouble. I need good facts for why i can get new tires and rim size and be o.k.