Maintence wise, you won't go wrong with a Porsche (look up reliability reports). A C4S is a great choice and I see you want to be safe with that IMS debacle. Anything non GT variant is going to be able to fit a back seat so your fine.
Don't get a chump mobile (BMW) as they aren't anywhere near the build quality of a Porsche and you'll always have the infamous and overly loaded electronics whizzes in the mobile to worry about long-term.
If you look hard enough, you can get an 08 C4S for a around that and they are going to be as reliable as the 09. If it was me, I would go for any year of the Turbo. You'll have the metzger engine (993, GT2, GT3) and you'll find your price range really quick. Maintaining them is no different than the a normal C4 and you'll be improving air quality as you drive.
Don't go BMW mate. POC