I'm looking at a boxster, but the seller does not state that it has traction control. The boxster does have 17" wheels and I see the traction control button. Does a tc button means the boxster has it?
TC button shouldn't be there without TC unless someone monkeyed with it. Check the option codes sticker under the hood or in the front cover of the maintenance manual. It should list M222 for traction control. I have always seen M222 coupled with M224 which is the automatic brake limited slip differential (note that this is not the same as a true limited slip and comes automatically with TC I believe).