I'm going to try the sport demons at my next track day i think - 110/70 and potentially 140/70. The pirelli guy is going to be there anyway, so why not.
The stock IRCs, once heated up, did a fine job (I couldn't beleive it) at my track day last weekend at Infineon (technical track). They looked pretty beat after though. I was running 27 front and 27 rear.