Wheel /tire size options
 

2003 boxster S. Wheel - 18"
OEM Tires 225/40/r18. Front
265/35/r18 Rear

I'm thinking of getting 2nd set wheels for winter / summer tires.
Do I need to stick with 18" to keep speedo accurate.?

What about the other dimensions ,how much variance is safe ?

Saw a set of wheels. Sized listed 18/8 front 18/10 rear. How can I know if these will work ?

Thanks

The 8 and 10 inch widths are probably from a 911. You need to compare the offsets of the wheels that you are considering versus the standard Boxster offsets. The wheels that I am running for the track have quite different offsets from my stock wheels. The rear wheels are pushed out considerably and the fronts needed spacers to give the car a good stance ( and to reduce understeer somewhat) with wider tires (235/40/18).