ADVICE for buying a used car

[McFaggarton]

anyone can read specs and all that but it's reliability that is something of a mystery to me when checking out a car. With that said, I would like someone's opinion on a GOOD FUN car with these specifications

Rear wheel drive
4+ seats
Manual transmission
Fun to drive (not looking for power so much as good handling considering the next criteria)
UNDER $15k. preferably WELL under, but that is my max.

The cars I am looking at now are some of the 5 series, found a few decently priced m5s too. Also looking at a civic or accord for the sheer economy of the thing. Oh, and yes, I've already found some cars but I know nothing of the cost of maintenance of any of them, opinions?