On Demolet's site, check the specifications page. No kits are labeled for sale for the saleen. Just look for the regular GT kits. Look for system #4 for the meter forward system, or system 5 for the upper pipe also. The upper pipe will most likely have to be modified to fit on your car.
A major reason I purchased a Saleen in the first place was because of it being a turn-key car, already “customized” so to speak. That only lasted a year.
I haven’t found a cure for the Mod Bug, but then again, I am not looking for one.