In fact in the 8/00 Car and driver the did a shoot out Cobra R vs Z06 vs Genn II Viper and the Cobra came in 1st, the the Z06, and 3rd was the Viper.
Was that C&D, or was it MT? As I recall, that was MT (the one where they dyno'ed all three cars), and it was the RT/10 that was included in that test. C&D tested them in February 2001 (this time with an ACR), and the Viper set the fastest lap times. Edmunds.com found the same in their test of all three at the Streets of Willow. C&D's Supercar Challenge of '02 also had the ACR coming out ahead of the Z06 (and that was with test editor Larry Webster against Heinricy in the Z06 against Hurley Haywood in the 996TT, which won that year).
Automobile Magazine tested the SRT-10 against the '02 Z06, and both had very similar cornering speeds: the Viper was marginally faster in some, the Z06 faster in others, with the Viper having only slightly faster cornering speeds on the whole.
The way I see it, it would be close like you said. But only if we're talking about the Z06.
SRT-10 vs C5 Corvette: SRT-10 (fairly comfortably)
SRT-10 vs Z06: tie
SRT-10 vs Comm. Ed. Z06 (Z16): probably the Z06
SRT-10 vs C6 Corvette: too soon to say, but probably the SRT-10
Slaloms & skidpads...in the slalom, the Z06 matches exactly the SRT-10 when both are tested head to head:
http://motortrend.com/roadtests/coupe/112_0306_spdtest_slalm_z.jpg
But trails rather noticeably on the skidpad portion:
http://motortrend.com/roadtests/coupe/112_0306_spdtest_totalper_z.jpg
The '04 Z06 with the revised shocks is said to be a much better handling car than the '03.