The local Ford service dept did the QDC fluid change over (TSB 11-11-1) today at 7220 miles, in response to my shifting concerns. I discussed adding XL-18 too with my service advisor (offered to pay for it), but since the TSB didn't call for it - he ended up not putting it in, and suggested that if I still had problems that it might be an option later. I could tell an immediate difference driving home - more like driving a sports car and less like a truck!
I'm still curious what additional information there may be from Ford regarding the advisability of adding XL-18 for my (June 2010 build) MT82, as I'm pretty sure the extent of my service advisor's research on the subject was limited to determining if my car qualified for the fluid change TSB.
2011 GT Coupe/MT82/Grabber Blue/Premium 401A/Anti-theft+HIDs/
Rear video/18" Polished Alum/3M Crystalline tint+clear bra/Hoen H10 fog/ES shifter bushing