From what I have seen and been told by others, it doesn't take a massive burnout to heat the ET's up but you still need to heat them. DR's on the other hand take a freaking huge burnout to heat them. I was having problems last year and asked a buddy how he heated his Nitto's up. He told me "Just do a burnout and look straight ahead. When you start to see smoke coming up to the front of the car, they're warm enough."
I thought he was crazy but it seemed to work.