roastpuff
Go Kart Champion
I was in the same boat, the car that was available had the 18's even though I'm going to be replacing them and their rotund 30lb weight.
I'm currently considering the neuspeeds or OZ super/ultra/whatever/leggeras.
Go for Team Dynamics! Cheaper than the other options mentioned here, and at 20lbs for 18x8 it's not shabby at all!
Neuspeeds are awesome, but at $400-500 a pop it's a bit out of my price range.