I spoke with Rossler at length about the different fluids and which is better and any advantages over the other - go to his web site and read what he recommends as it applies to torque flites also - personally I run the Dex/Merc - Pennzoil if I can find it or Castrol seams to work just fine also - main thing he advised me was watch your trans temp - heat kills things quicker than anything and synthetics are not a must - unless you cant get the heat out of the transmission between rounds. Some of the Chevy guys that go many rounds run the Mobil Delvac 1 ATF or equivalent made for Allison Transmissions - seems to have good heat properties.

http://www.rosslertrans.com/tech.html