These are the Quarter Window Scoops that were originally produced by Thomas#142 on the ffcars forum.  Since he is no longer producing these, we have reproduced this design for you.  These are fiberglass parts with black gelcoat.

On the GTM that I test fit the original pair on that we pulled these moulds from, the LH scoop fit fairly well.  The RH scoop was very much undersized.  The whole rear of the scoop was about a half inch from filling in the recess in the body width-wise….from just a few inches behind the leading edge, all the way to the rear of the recess.  For this reason, I took a ton of extra time and “extended” every edge of these scoops so that you can custom fit them to your particular GTM for a perfect fit.  I intentionally left a ridge in the mould so that you can see the exact size and shape of the original parts that the moulds were made from.  I highlighted this ridge with purple metallic marker in some of the photos so you can see what I’m talking about.  Once you get the parts trimmed down to size to fit your GTM, you should be very close to that ridge on the LH side, and fairly close on the RH side.  Your best bet is going to be to slowly trim away the outside and keep test fitting to see where more material needs to be removed until you have a perfect fit to your car.  Trimming parts to fit is always going to be much faster and much easier than trying to make an undersized part fit an oversized opening.

This set comes with the LH & RH scoops as well as LH & RH “patch panels” to fill in the “window opening” that FFR cuts into the body in that location.  I would recommend cutting the patch panels to an exact fit to the opening, bonding them in with 8115 panelbonding adhesive, then put a couple layers of fiberglass matte and resin over the whole inside area of the body to reinforce the opening.

You can see these scoops installed on the #12 GTM on the home page of my website.