Let me put this into perspective when you guys are shoping for wheels. If the stock wheels weight 15 pounds each (which is really light, Im just using that as an example) and you buy some aftermarket wheels which are 20 pounds each, then in theroy you are only gainging 20 poudns total on your car. (4 wheelx times 5 poudns mroe each = 20 more pounds) HOWEVER this is not the case. I forget the forumla but for every pound you add to the wheels it will be the ame as adding 15 pounds to the body. So in reailty you are adding 75 pounds to the cars with those heavier wheels.
Just something to think about. My 1986 Buick Regal T-type was faster than the Grandnationls because the wheels were alluminum while a GN's were heavy-ass steel.