Thanks greg, i understand that the kits you mentioned are basically all the same principle. however, i see that fabtech recommends a 17x9 wheel with 5" backspace. now, maybe i'm not understanding this correctly, but in that case, shouldn't a 18x8" wheel with 5" backspace fit with no problems whatsoever?? My understanding of it is that the backspace is the same, so the extra width is gained towards the outside of the rim, correct?? Let me make sure i'm understanding backspace correctly, it is the measurement from the mounting surface to the inner most point of the wheel? correct? But offset is what I'm not exactly understanding? I've read before that the stock 18" wheels are 5" BS and -25mm Offset. so that means that it is 25 mm from the centerline of the wheel towards the outside to the mounting surface? I know its all pretty simple really, just having some trouble comprehending at the moment. I've got the 6" Procomp on the way, and want to be sure my stock wheels will work b4 i go and put it on. Thanks everyone for your help. Can't say that I've been on any site thats been this helpful...although, i've had alot of problems with my Cannondale Quad, and there are some pretty helpful forums out ther for it. This is a great site though.
oh yeah, just found this site here with some good explanations:
http://www.usacomp.com/Offset.htm
what i don't understand is i'm looking at a wheel site with 18x9 wheels, 5" BS, and +2mm offset. according to the site i mention above, offset would be 4.5-5"=-1/2" which doesn't = 2mm??? i guess that's why i'm confused
if anyone can offer any explanation it would be appreciated.