You're probably going to get a lot of different opinions. So get ready for it. Opinions are like buttholes, everyone has one.
He's what I'm running in 5 years of ownership:
Oil - Mobile 1 0-40 - recommended weight in new Vipers, and IMO the best fit in the older guys as well. I like the additives in it as well.
Diff - Mobile 1 75W-140, I also added the LS modifier
Trans - Pennzoil Syncromesh - I know it calls for Dex III, but I lost 5th and 6th gear and did a rebuild on the Viper and Vette. Both are running Syncromesh now. I have seen no ill affects and have done some research on it
Coolant - Haters going to come after me on this. I run Dexcool in the Viper. I think its very similar to Mopar Orange, and have done a proper flush of the green before, after 5 years and every other year changes, Car is great. Did some research and I'm prob not the only one running Dexcool.
Brake Fluid/Clutch - Prestone DOT 4
Power Steering - Royal purple synth