to keep up with some of the big boys, the Boxster is going to need some proper rubber. We have a great tire contingency program with Yokohama available with free slicks available. That was actually one of the deciding factors on converting the car for GT racing initially. To be competitive, I figure I will need either 240 or 250 fronts and 280 rears. Fitting these under stock Boxster steel is quite difficult.
I ended up getting myself two set of 18x9 and 18x10.5 wheels from Jongbloed. They were real quick and easy to work with. I had them all hard anodized and I think they look pretty sharp on the car. I mounted up some used 240/280's for fitment and found out there was a need for some bodywork.