Forums are usually ok b/c they're like fan sites..but if its parked for pure ppc..expect a c&d letter eventually...
Every tm'd auto domain I've owned, that was just parked for ppc, has received a C&D Letter..mainly higher end autos (porsche, mercedes,ferrari,etc)
I'd say $0 b/c of the TM. unless it gets good traffic/income, you may get 1-2 years income if you're lucky..
just IMO though..