Well i have been researching lightweight sports seats. But have come upon a hurdle. Seat runners for aftermarket seats. No one makes them. My original idea was to find some carbon backed sabelt seats from a fiat 500 or even better a rare Alfa mito SBK, as these would fit to my oem seat runners. Thing is the sabelt sports seats once fitted are a lot higher without adjustment than the GT's oem. So again this needs research. The 156 is listed for aftermarket seat frames, are these the same as the GT's?