G8 is nice. CTS is a great car also, but dude if your thinking of dumping the camaro because you keep hitting your head. STOP HITTING YOUR HEAD!!!! Clearly the damage is affecting your judgement. lol
But seriously I'm 6'3" and maybe I'm just used to watching out for things that may do harm to my noggin but just duck down further. You're probably just so excited to get into it you dive on in. Take it easy and you'll be fine.