Can't speak for the 8, but here's me in the 4..... 6'2" with plenty of room to spare. It gets a bit tighter with my 'chute on but even inverted I've got good clearance
Head room is much better in the -8. Again, I am 6'4" and have plenty of room between my headset and the canopy. In my buddies -7 my headset tapped on the canopy at certain times.