There are only a couple options for tire sizes based upon your wheel sizes. The 345mm tire is available, but I believe that sidewall is larger so the rear of your car will ride 1/2"+ higher. Unless you have adjustable suspesion, your handling may actually suffer and the car may not be balanced well. We have seen 335s up front too, but I would not recommend that on a 10" wide wheel. I would recommend no more than a 295mm wide tire on that size front wheel.
If you can lower your car (adj. suspension), I would recommend the Michelin Pilot sports 345/30/19 for the rears with the 295/30/18 for the fronts.
We order and ship many tires for Viper owners. We'll try and get you competitive prices.
Hope we can help.
-Wayne (LTHL VPR)