I also have an 02 sc430. I got BBS wheels which are probably better than what comes on the Lexus. The only trouble I have had is that they seem to leak down every couple of months.
I had them put on a the Goodyear dealer where I got them. They had by far the best price. There are Korean, and Chinese knock offs of BBS which will crack and show dust marks after you have had them for a while. Of course they are about half price but I figured I'm going to keep the car for a while so why not get the best. They were plasma finish (not so shinney as the chrome) and cost $2500. installed.