>I wouldn't worry too much about weight... I mean you might
>save a few pounds but nothing that would hardly increase of
>decrease performance.

It's not about the overall weight of your vehicle, it's about calculating rotational mass. The total weight of the wheel will directly effect the engines ability to turn them. It's called rotational inertia.

The quicker you can get your tires turning the faster your car is (obviously)...so why put heavier wheels on and slow it down. Why do guys go to the track with stock RS 14's, because they are super light. But if you take the 14's with tire and stand them next to a 17 w/tire they are the same overal diameter. So it's not about diameter at all.

If you don't believe me take a dowel rod and cut two equal diameter pieces of wood (use the same type). Drill a hole in the wooden disks and put the dowel rod into only one of the disks then spin it with your hands. Get a feel for it then ad the second disk to the end. You are effectively doubling the weight (I know it's cuz there's two there, but the number doesn't matter). Now spin it with your hands and you'll see it feels "heavier" or harder to spin. This is the theory behind lighter rims It's all about rotational interia.

I wish I had a set of OZ Supperlaggera wheels. They are incredibly light (15's weigh 11lbs and the 18's are still less than 20). Hell, I'd go to the track with two sets of wheels to prove this if I had the money LOL (still on 14's)