It would be alot easier to tune your Viper if you told us what Viper you have!! If you have the GTS, then set the Gear Ratio auto setting to about 34 or 35, or do them your self. For downforce, I would say have them pretty low, but never make the back downforce stronger that the front, the front end tends to fly up a little. Put the Final Drive Gear at about 2.500 or something around there.
Hope you get your car working!!
-Sam