I have a 2002 s-10 lowered 3" up front and 4" out back, whats the biggest rim i can fit without it causing problems. And also could you tell me the difference between a FWD rim and a RWD rim...and could i put a FWD rim on my truck...thanks

the difference between a "FWD" rim and a "RWD" rim is typically the offset. It depends on the rim size and the actual offset of the FWD wheel in question to determine if it would fit on your truck. I've seen S10's with 22's but they had to cut stuf to make them fit. Usually the biggest you can fit without cutting is 20's

w/ a 3/4 drop 20s are going to probably going to scrape on a big bump. Go to a shop that sells custom rims they will be able to tell you for sure, thats probably your best bet. w/o seeing the truck i couldnt tell you.