The r8 handles better, more technology (since the viper basically has the same interio features as our cars LOL). Unless they are adding the new navs to teh viper, the 03s and such still had the rb1 as the highest thing.
The audi is 4wd, mid engine car that wont lose control.
its also a well built v8 4.2L
Overall its apples and oranges, viper fans will take the viper over any other car despite the price tag and gas costs. Audi owners will do the same, although most will agree the r8 is a very sexy car.
Some of the new audis are all on the same design of the r8, even the a4 has taken a new shape, mainly in the headlights of course.