I thought you might reference me!
I'm 6'4 - 6'5 and in the mid 3's. I don't have a ton of extra room, but it fits me well, and having been in a major front end collision, I didn't hit the dash with my knees or anything. I have the seat all the way back (naturally) and the seat back leaning a bit (I like a bit more of the F1 reclined driving posture over upright). I'm not sure I can wear a helmet with the stock seat, but I like it.
Go try one out, they're pretty easy to find examples of.