Hey there, I have a manual 2011 mustang gt with 3.31's currently installed and 6000 miles on the car. I recently purchased ford racing 3.73 gears which included the pinion, pinion nut, gear, shims, and crush ring. Do I need anything else like bearings or seals. Also I plan on putting 75W140 royal purple and I was wondering if I need to add ford friction modifier, and if so, how much do I need to add? Thanks for your help.