Bikey

The little F1 plates are steel, but less then the 3mm thickness (~1/8") needed for FIA mount, which is a pretty good guideline to go by.
Aluminum needs to be a bit thicker (5mm).

pgss2k - do you have the regular 2 piece brackets (one piece per side)? They do not allow a very low position.

pgss2k

my side plates are one piece per side (2 only) and aluminum of fia rated thickness. The reason I went down this road was for safety. Seems like my seat bottom might not fit below the rails of anything that uses the stock mounting points. 16 1/2-6 5/8" seat bottom

Bikey

So, even if you had the little F1 mounts, they wouldn't do you any good?

Seems like the SPG fits btw pretty well from the above pics - what seat are you using?

If you want to maintain FIA spec, you can have a local metal shop bend up some brackets like the F1 shorties out of 1/8" steel, then you drill the appropriate holes.

pgss2k

Not sure if the seat wont fit or not. I have been fooling with it for the past couple of hours and managed to get about 1/2 of what I wanted rearward and am low enough w/o the seat padding in place. Leaning towards your idea of fabbing up some sideplates. Seat is cobra imola pro gt. got that one because it is hans compatible when I get there ($$$).

Bikey

I'm not sure what makes a seat HANS compatible, since their function is dependent on the harnesses.

You may also consider a Safety Solutions Hybrid Pro Rage - cheaper and tests much better than the HANS.

Why can't you get it back far enough - you are on sliders, correct?