Bride FX-Type rails are probably the lowest "bolt-on" solution without slider:
products
N161FX & N162FX are the part numbers left and right.
Pole position is a pretty wide seat, you may need to go with the Recaro, Sparco or Bride XL/Wide brackets with sliders. Or just drive down to Wedge and get some custom ones made.
www.wedgeegineering.net