Hi mate,
the scuffing of the inner edges of the rear tyres is caused by hard acceleration, the back of the car squats under power causing the camber angle to go negative (that is the top of the wheels incline inwards at the top) this causes increased loadings on the inner edges of the tyres thus increased wear in this area.
This is not a problem with suspension geometery a lot of cars with similar rear suspension show this trait.

CheeRS, Mike.