19's on a Box

[No_Name]

1. For a safe bet, you can go with the sizes of the OEM optional 19" wheel/tire pkg. (assuming 986 and 987 have similar offsets)

2. As long as you have the correct offset, wheel/tire width and respective tire profile, you can fit 20" or larger. Remember, the overall diameter should not change or changes very little. Larger wheel is compensated by lower profile (sidewall) tire.

My humble opinion is that anything larger/wider than 18" 235/265 will only hurt the boxster's performance... unless you have some good reasons under the trunk that suggest otherwise.