Those pads are not meant for any track. I run Pagid RS29s in my RS5 Calipers (the same as the RS6) on my B8 S4 (almost 4k lbs and similiar wheel base) and it stops just fine. If you pursue more track events I would get a different set of pads and run them for the events. Also with the brake fluid Flush once a year and if you have event with lots of fade, bleed the calipers before the next one.
Have you found a good place to get these pads from?