Definately the Challenger. Make mine a 5.7 with 6 speed, and I can use the rest on modifications. By the time it was tweaked, it could probably hang with the Viper on power, braking, handling, etc.
no offense but you have never driven a viper have you? As someone who gets to drive a new challenger from time to time and a viper a few times it's not even close, the viper wins hands down for go and handling. Now if I had to buy one for myself I think I would go viper because you are starting to see challengers every day but vipers not so much. Not to mention Vipers are just fun to drive! And yes I would DD it just like I do with my swinger right now.