Go with the RS60, in my opinion. Yes, some other Boxsters could come with red interior, but why spend time digging around searching for one when you've got it right there available to you? If everything checks out well and it's a car you like, go for it. It's an S, miles are decent, and you know it was actually driven, and therefore, more likely to be regularly maintained.

Checkout my 2000S:
Boxster S pictures by OldHippieYoungHeart - Photobucket