The Z seats mount lower than the plastic racing seat I had on the drivers side, and the same, if not lower than the stock passenger seat, and that is with 3 of the plastic spacers in the rear and (one spacer up front on the passenger side only), as the drivers side has a height adjuster. As far as leg room, It would be about the same also. I'm limited in how far back they go by contact with the roll bar.
Overall, the seat itself is the same width, height and thickness as the original seats.