hey guys i have a 14 second iroc and im thinking slicks will get it in the 13's, does anyone know what size rear rims and tires i can get cheapest???? right now i have 16 inch rims on it im thinking 15's for the slicks give me some ideas thanks

 

Whatever you can afford. A typical 15 x 8 rim with 3-4" of backspace. 26 x 10 slicks should do you just fine. Until you start doing measuring to see the best rim and tire fit, that should be a good start.

Slicks won't necessarily make you faster but they should make you more consistant by reducing or eliminating wheel spin.

 

What brakes do you have on the rear? You may run into problems going from the 16" rims to 15" rims. On my 89 Formula I had the 11.65" rotors, and a 15" rim would not clear the calipers.