I have an E-55 along with the two Vipers listed in my signature. The E-55 will spank most Vipers from a stop. I haven't lost to one yet (other than my own) while cruising. I do shut down about 75 - 80 mph, not wanting to push my luck.
Most Viper owners run Pilot Sports - stock tires - which are really worthless for launching the car. Combine that with limited driver "drag racing" skills, a little bit of excitement and you have a very powerful car, the Viper, that can be made to look silly beside a four door sedan from a stop light. Going from a roll is another story, especially a fast roll.
My SRT-10 is a beast. I run it with drag radials on the street. It eats the E-55 from any speed, including a stop. The GTS does pretty well too. The cam I had installed by WCV pulls very hard from right off idle, so starting quickly by slipping the clutch is easy.
The E-55 is under rated from a hp / tq stand point, perhaps for insurance or marketing reasons, who knows. If you are running stock tires and aren't good at launching your car, don't test one from a stop, stick with the "roll" approach.
Lots of fun.
Dan