Josh, from the man who actually build the FRS:
"As for fitting the Stage 1 with the Stillen, I think it could be done. The concern is the fuel rail inlet fitting at the front of the valvecover. Its very close to where Stillen puts the throttles and charge pipe. I was unable to get a local Stillen car for testing the Stage 1 fitment on, and from pictures it looks like it will require some bending and tweaking of the fuel inlet tube. I am sure it could be made to fit, I just didn’t want anyone to complain about having to modify the inlet tube.
Charles @ CJ Motorsports
630-715-1077
www.cj-motorsports.com"
As said jez is getting it sorted one way or another , I guess you are always going to have little issues to solve and that's why it's in his capable hands