Michelin Super Sport Tires
 

I have a 2006 Boxster S with 18 in wheels. Currently, I am using stock Michelin Pilot Spost PS2's (235/40-18 on Front and 265/40-18 Rear) with Porsche 5mm spacers all around. I will probably need tires soon and saw several great reviews on the new Michelin Super Sport tires. Michelin only offers the Super Sport in 245/40-18 for the fronts. Will I have any trouble using 10mm wider tires on the front? Will there be any rubbing on tight turns? I don't want to spend all that money and have tire damage. Any thoughts?

Can't help with your sizing question but they do look like awesome tires:

Porsche Purist Review: 993c4s.com/porsche-products/tires-and-wheels/testing-michelin-super-sport-cup-dubai/

The 245/40 will be also taller than the 235/40's, hopefully you can find 245/35 to keep the same diameter

When I bought my car it had 245/40/18 and they rubbed on the inside fender liner. I went back to stock size when I replaced the tires.

IIRC they will fit fine, but you will probably need a spacer. Do a search on wheel/tires sizes. To keep the relative front to rear dimeters the same, you could go up to a 275/40 tires if it's available, though there shouldn't be a problem with the 245/265 combination.

Michelin only sells 245/40/18 for the Pilot Super Sport? Tire Rack lists that tire in 225/40/18. Sells for $238 ea.