Fifteen inch tires and wheels are by far the most popular. IF you're a beginner I suggest the cheapest wheels you can find because they are going to get ripped to pieces. There's no downside to using steel wheels either, they're actually cheaper and stronger....just don't look as pretty and may be a little heavier. The 15 inch size gives the tire some sidewall which is critical for a rally tire. Goodyear, Michelin, Kumho and Falken make rally specific tires. They arn't cheap and like most racing tires don't last very long. The Falkens and Kumhos are a little more affordable. I got away with using Cooper weather/winter master snow tires for awhile. They're cheap and have two ply sidewalls (most tires now a days only have one ply sidewalls) and a open agressive tread. They're no where near the performance of a dedicated rally tire but once again good for beginners in a slower car (non-four wheel drive and/or turbo'd).Awesome, what about wheel and tire sizes, I know i need to upgrade the breaks, Im just more so concerned with replacing the wheels.