jarrod-xr6t

hi all im am new to forums and would like to find out why my diff makes alot of noise on wheel spin, I have an fg xr6 turbo manual 2011 with only 12,000ks every time I get wheel spin in the wet or dry I get a really loud noise from the diff as if its bouncing or something like the term (axel jump) but I noticed if I really get the wheels spinning quick in 2nd gear the noise is not there?

hi I was wondering how the car would sound with a cat back exhaust also the best setup just because I dont want to void the warranty?