Remember the RS has bigger front calipers and bigger, drilled, discs, so the thermal capacity is significantly greater (it is also 100kg lighter). Certainly the dust shields aren't likely to be helping - they just stop air flowing around the back of the disc.

Brake late and hard - you will be surprised what you can get away with if your tyres and geometry are good !

 

I'm a track day novice but I noticed only the smallest amount of brake fade on my standard set up (no ducts and 2 pot rears) and cheap aftermarket pads at the Snetterton, the Ring and Spa last year.

But better drivers might put more heat in to their brakes (and be breaking from greater speeds).