I have a used Sparco Speed seat in great condition. There is no signs of wear on the bolsters or fabric. It is black and comes with the brackets to bolt to a OEM FC driver side seat base. This keeps the seat as low as possible. I am 6'3 and my helmet does not hit the headliner with this seat and bracket.
The seat is only 18.7 lbs and very solid.
All you need to do is take your stock driver seat off its base, and bolt this seat to your original base. You could have this installed in 20 minutes. In the second picture you can see the seat is mounted to the FC slider.
$220 picked up in Orange County. If you want the harness shown, I will sell both for $260.