No. I first sat in the driver seat, set it up correctly for me, then sat behind it at the back. It was ok! Knees did not touch the seat and just enough headroom. Only with the glass roof though, head hits the roof with the regular roof. About 2cm difference.At 6'4" in the back, I assume the front seat is pushed up pretty far...
An update for anyone else who was worried about this same issue. My dealer knows I have been worried about this and was very nice to call as soon as the demo car arrived. As a result, I was lucky enough to drive a Turbo S today, and wow...but that is another thread.People are built differently even if they are equally tall. There is not that much space so it will depend on how you're built. Only way to know for sure is to test it yourself but I know for sure it is *possible* for a 6'4 driver & passenger to fit back to back. Not guaranteed.
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But as for the driver seat, I'm certain it will be fine even if you're 6'6.