Buy an 86-89 Porsche 911 that's already had some good work done to it in the last 10,000KM-20,000KM and you'll be able to sell it in one to two years at the same price or a profit. If you want it to be even more summery, get a Targa. But don't get a Cab, they're ugly.
My 2 cents
Edit: The 86 will have the 915 tranny, the 87-89 will have the G50. Some people like the G50 better and others prefer the 915.