The RS3 is a very good tire. Sharper steering than a PR4GT. Maybe too sharp and neutral. But you really should run BusyLittleShop's Pirelli Diablo Supercorsa SP to keep him busy mounting new tires every 2000 miles.
6500 miles on a rear PR4GT? One shifts hard? Downshifts hard between gears? Upshifts hard too? Slams throttle shut a lot?
I get 9,000 to 10,000 miles on rear PR4GT with a heavier FJR1300. I don't find a difference in tire life between Michelin PR4 and PR4GT, but I find a significant longer life of Bridgestone T30 Evo GT vs T30 Evo. My favorite front tire was a T31GT which ran 9500 miles and handled same as new to the very end. No longer available so I have a T32GT mounted now, PR4GT rear. For some reason I like the mushy PR4GT on rear and stiffer T32GT on the front. I really do not like PR4GT on front. And for some reason I don't like T30 or T31 on rear.
Having said all that, a set of new RS4s is waiting for when my current tires show cords.
I had 6500 miles on it when I changed it. There was still some life left, maybe a thousand or so miles? But, I was heading out for two week trip and didn't think it would make it. I loved the performance of the PR4GT, but comparing them to the T31s I have on now, the T31s perform great and are lasting longer. AND, the T31s were about $100 a set less expensive.