the other thing I would look at is transfer case. I have a similar problem in my 32 GTR. car is a nugget at corner exit. revs flare up, sounds like wheel spin, but the attitude of the car changes very little (if at all) which lead me to thing clutch slip, but I cannot replicate it in a straight line, and loadded up, launching, shifting hard whatever the clutch does not slip. which has brought me to conclude slipping transfer case. an easy way to find out is if it's trasfer or diff is do a few laps in RWD and see if you still get the same feeling. if you do, then obviously it's diff, if not then I would be looking at transfer. good suspension wont hurt it either though.