6'4", size 52 jacket. I put the seat all the way back and all the way down and my legs just fit on the pedals. I can't stretch them all the way out, but there is enough room to be comfortable. Headroom is also enough, but I would prefer to be a tad lower for visibility. The rear-view mirror gets in the way a bit, so you have to kind of duck your head to check under it since the car is so low. But my head pokes out of a Miata, so I'm happy.
Having seen the car in person, they weren't joking when they say they minimized CoG height. I see why they went with a boxer because the thing is SO LOW. The transmission tunnel is an inch away from the top of the engine, and there is plenty of room for a turbo behind the engine. If they could find a way to move the tranny rearward, they could easily fit a 6 cylinder under the hood. Only a boxer would fit though. Anything else would need a stupid-huge hood scoop.