Not unless the driver in the GTS sucks (which is a good chance because most guys don't know how to drive their Snakes). Equal drivers (unmodified cars), the GTS will smack the SVT all over the place (except in OE braking). The SVT will have a better chance against the Gen 1 Viper.
The prices on used Vipers has dropped dramatically (because of the bad economy), why would anyone buy and SVT over a used Viper?
JMO.