18in rims for my 02 Boxster s will these fit without mods?

[Ckrikos]

10" will fit in the rear, but you will have to tie down and possibly readjust the parking brake line. The 65 offset will be your problem. You need to bring the offset to 40 or lower, so you will need to run spacers.

[Johnny Danger]

The fronts will fit, but with a +50 offset, I'm certain that you won't be happy with the way they look. As far as the rears are concerned, +65 is way too high of an offset. However, depending upon what size tire you're using, I wouldn't recommend lowering the offset any more than +45 to + 40.