RE: E rs4 for drifter
Sweet, dude!
I think you'll be happy with the performance of those tires. I've been using them for a year now, and my first set of DXPE's are STILLmounted, and sliding! The other two sets are on other drifters, and are barely worn!
The D68's are good, as well. They are a harder compound, so they are restricted, somewhat, to the surfaces they like best. You'll have fun testing them out, though!