I don't know where vintage42 stores his 6'2" when he sits in his car. I'm 6'2" and no matter what I do, I can't drive without bending my right leg so much that it is not supported by the seat. To get the seat back so my right leg is close to straight, I have to have the seatback close to vertical and the seat raised enough that my head touches the soft top. Also, I'm only 190 lbs and the seat is comfortably snug. Depending on where you carry the extra 40 lbs., you might find the seating snug in additional dimensions.
I'm driving an M Roadster, so the seats may be different in a regular Z3. In any case, it is all worth it. I love driving the car, and except for my right leg, the seats are very comfortable. Once on the highway, I can engage cruise, stretch my right let under the brake peddle and be comfortable.