How much you want to spend? The wheels are one thing. The tires that go on them keep getting more expensive the larger the rim size. I prefer 17" but I've seen 18"s that look and function really good. I keep away from "Z rated" tires. They tend to burn up and the need to be replaced sooner than "W rated" I go with "M+S" for every day driving, but keep another set in the garage for play. Mickey Thompson makes a good pair of slicks for a 17" wheel. Also, the larger the rim size the more your suspension will have to work harder and you will feel a more rough ride. So it's a trade off with looking cool rollin on 20"s versus a comfortable car that can run on 17"s or 18"s that people like to ride in with you. Hope this helped a little.
__________________ DRIVE IT LIKE I STOLE IT!!!
Avatar picture not my actual car.
97' GT Cold Air Intake,HHeaders,Xpipe,flows,
NO CATS (yet) 3.55 Gears,short throw shifter, subframe connectors,tower brace,cowl hood,boss spoiler,lower'd 2"front 1 1/2"rear. 245/45/R17s front 275/40/17s rear. | 
Rims size 18-20in. 
