You can get nearly ANY aftermarket wheel to fit our cars, just pick what you like. On a Cutlass, I am very partial to the factory 15" Olds Rallye wheels. I run them on my 80 Cutlass. I got them from the wrecking yard off of a 70's big cutlass. They were chromed and used on the 442s in the 80's as well.
As for performance, the sky really is the limit there as well. You can turbo, like the
Grand National, or make a fair amount of power naturally aspirated as well. You need to ask before you spend any money, what is your performance goal? Daily driver with pep, or serious street machine? We'll start there.
Here are some mods you need to do regardless of what else. You need to upgrade your transmission to a 2004R so that you have overdrive and more performance parts available to you and then make sure your rear end is somewhere in the 3.4x to 3.5x range. You'll get better take off and a little more gas mileage. If you jump up to 15" or bigger wheels, you'll appreciate these mods even more.
