LOL, at least 3 of the toasted transmissions posted on DT were R/T's, and one that wasn't was a 4x4 running an R/T torque converter and 4.10 gears
So although cooler is better, its not going to save you from breaking.
I have the HD cooling on my 4G 4x4 with Tow package, pretty sure all 4x4's get it on 4G Hemi Rams.
My Trans temps are around130º city commuting, peak at around 150º driving it hard, flat out racing at the track in back to back runs might reach 170º
...and that's with an Edge 3000 stall torque
only trans mod so far is the Sonnax line pressure booster while I search for a used 545RFE to rebuild.
The weak overdrive frictions from 3rd gear (and beyond) and the lack of enough pressure to hold the clutch packs without slipping is burning them up.
If you dont want to baby it, you need better frictions with larger surface on clutches/steels and a line pressure booster to hold them tightly together to avoid burning the friction material off.
Higher HP/TQ needs more pressure on the clutches, its just that simple, and the better your clutch pack the longer your trans will stand up to abuse.