I fitted Mk2 MX5 seats to my road-going Spitfire, and as there are only two of us who drive the car (and we about the same height - 5'9") I removed the Mazda subframes completely and bolted the seat bases through the floor with square spreader plates underneath. They were then slightly too low, so the drivers seat is now supported by metal bobbins approx 1.5" high. They are firm, comfortable and supportive with adjustable backrest and headrests. I used the LH seat on the RH drivers side, and vica-versa The one mistake I made was assuming the LH seat base mountings were identical (or at least a mirror image of the RH seat) It's not, and having made only one cardboard template for drilling the floor, I had to weld up a few spare holes! The race car has a Kirkey unpadded aluminium seat on competition mountings, which is actually more comfortable than it sounds - but then most racetracks don't have too many potholes.