Well, you're correct in that it's a very long answer... there are quite a few files with many data points in each one, and the more of those you can measure or research, the better your car will be. (There will inevitably be some things you don't know, and in that case you have to set things up by feel, but the fewer, the better.)
As far as the Viper is concerned, if you'd like an unlocked set of files from our NFS Viper (an early 90s model) drop me a PM and I can share whatever's in there that might be useful. And I'm happy to help you modify them to better match your 04. It's a lot of fun driving your own car in AC.
Hmm, I may have to take you up on that at some point. My sim rig has been sitting unused in the basement for a while now. Might give me more excuse to use it if I had something I really wanted to drive. I had talked with A3DR about doing a gen 3 Viper at some point in the future, but I know he's got plenty of other projects on his list, so mine was more of a "if you're ever bored" kinda thing. Having the car sitting in my garage and all the service manual stuff for it as well as a dyno sheet makes it a bit easier at least.