Personally I'd buy a receiver that you mount behind dash with a cd changer port (later when money alows), IPOD port, and a good remote control. That way you can literally hide the receiver behind the dash with nothing exposed. Thats what I'm doing with my truck and my sons Elky. Myself I never use a cassette any more and the Ipod is awesome for storing the songs you like....or in my case....rather listen to just the radio anyway.

I met a guy a couple years ago with a 60's classic car. He had his radio disguised as a underdash A/C unit.....in the same fashion as what I said above. Really neat. But no air.