Very interesting as you certainly have gotten great dyno results. A lot of it appears to be due to using a ported cobra jet manifold, special throttle body, and an AED tune. I assume you used a dynojet dyno.
I have the same headers with the cats, stock manifold, and Bama tunes and can only manage about 380 hp. I have the kooks catless pipes purchased already but I think my car would get way to loud since it is pretty loud right now. I am tempted to find out what it sounds like and what my gains might be. And after that I am strongly considering an AED tune but not sure if he can tune with Diablosport tuner.
2013 GT, Track Pack
, Recaros, Kooks Axlebacks, Airaid CAI, BMR Rear Adj. LCAs, BMR Relocation Brackets
, JLT Oil Separator(s), Barton 2 Post Shifter Bracket
, Steeda Motor Mounts
, Barton Shifter
, JHR Clutch line, BMR adj. UCA and Mount, Kooks 1 3/4 headers/catted H, DSS Al Shaft
, BMR Loop
, Vogtland Sport Springs front/BMR rear, Strange Adj. Struts/Shocks, Extended ball joints, Steeda Bumpsteer Kit, Whiteline Tranny Mount Bushing, Borla Overaxles, BMR Watts, Vorshlag 3" Ducts