I'm 6'3" as well, and I've never had a problem with headroom in any FC's I've owned. Helmets can get uncomfortable on track days, but certain aftermarket seats sit lower than stock. I have MOMO RS GT seats and they sit an inch or two lower than stock on Wedge brackets. I've always had a problem with the steering wheel sitting on my knees, but I've been using an extension for past couple years with great results.

 

thanks for all the help guys.. and as for having the seat nearly straight upright, i cant drive like that.. bad posture and a fucked back (lol and im only 22) eliminate that option anyway, that said i do lean it back, but i dont like to lay down. its still fairly upright but on an angle :s, but the sounds of things i should be pretty right with the turbo model (which im gona get anyway), thanks for all the help guys great forum! only it doenst work for me sometimes.. wont load..

 

6'4" no problem sitting in the GXL. Granted I had to shove the seat all the way back, and recline a bit, but I fit and didn't hit my head (not even when I wrecked).