Interesting, yea I would agree its happening when one side of the axle gets compressed. what offset and backspacing are your rims?
this is what was in my modification spreadsheet. this confuses me when i look at 2016 catalog. maybe there have been changes since 2013. i will double check when i get home in couple days.
Drag Star Rear Racing Rims 92-580150 DP 600 dollars 8/21/13 15x8's, 5x4.5" bolt Cir., 5.25" backspace, 25 mm offset
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