What is your goal? You've got the 18 specified but how wide would you like. Most wheel vendors/mfgs can provide the help you need but you'll have to tell them a little more about your suspension/brakes. Its often helpful to rough-out line your build starting at the core and working out; I'd recommend you try and set your scope, intent budget (ex. I think/know I'll be using a stock 12 bolt with 13 inch brakes on the front 12/rear). Don't be afraid to do a little research; Don't forget team camaro and lateral-g; I'd say there are several recipes well documented on the sites, plus more sponsors.