I'm sorry I never mess with car audio, so forgive me if this sounds stupid, but I was on crutchfield‚Äôs site looking for reviews on a head unit a friend of mine is selling. Crutchfield says double din head units will not fit our cars!? Anyone put one in yet? My friend is selling a Panasonic CQ-VD6503U. Anybody have an opinion on that head unit?