Pulling timing may also raise EGT's , imo the RS is just too small for a 2.5 that spends lots of time at WOT
but, plenty of people use them (and similar) with no probs, I ran 20psi with a little high flow with no dramas even after a 40 min sesh at wakie
if its detonating than the tune is to blame, I would add more fuel before pulling timing (due to above) who cares if you lose 5-10 killerwasps