Hmmm... So far all of the answers have focused on margaritas. Coincidence?
For sauce, turn it in at the temp that the sauce tastes best. Yeah, I know that's a wishy-washy answer, but some sauces taste better cold. I prefer warm, and that's what we usually turn in, but our best sauce finish so far is 4th place, so i may not be the best person to ask.