That's the thousand dollar question.
I worried and read everything I could find here at allfordmustangs and elsewhere regarding MTL, Amsoil, BG II and the rest of the trans
I even have some MTL here in my garage.
But I never used it.
I ended up staying put and doing a change and refill of QDC and there was a lot of difference from the original fill.
My build date was 1/12 so QDC was originally in it. But the new fill was a game changer for me.
Why I don't know.
2012 Shelby American Mustang GTS 580rwhp 485 ft/lbs Grabber Blue White Stripes
Ford Whipple, 5.0L, Tremec XL Magnum, MGW, Centerforce DYAD clutch, Boss 302 Torsen w/4:10s, 302R EPAS, Eibach Coil Overs, Fays 2 Watts Link, Dynotech DS, Shelby UCAs/LCAs, Wilwood brakes 6 piston 4 piston, Drake Bump Steer, heavy duty cooling, welded axle tubes, Interior Package, GT4 wheels, Borla Touring axlebacks, GT500 rear valence w/parking sensors, and airbag cover signed by Carroll Shelby.