As far as I know, most of these cars have only bolt-on mods.
A stock SS runs high 13's in the 1/4 mile. This has been reported by the mags and the owners. Therefore, a modified GS would hang, and a modified GP has a very good chance of taking a stock SS in the 1/4 mile. If the SS is modified, then all bets are off.
I definitely am not a good driver - using any definition. Learned to drive when was 45, after immigrating 5 years ago. Still uneasy when merging on highway after dark. Would never take a risk intentionally, even more engage in race on public roads.
Though, it is a child play to "blow away" a V-6 Camaro during the usual driving - like when you are sitting at a traffic light and need to change lane before the next traffic light. No place to "maybe". Just pull smoothly, to not burn tires, and after you see the Camaro headlights in the rear view mirror (not the side one), you can lit your turn signal to change lanes couple of seconds later.
Though, the SS is doing the same with GS equally easy. Have the first-hand experience.
This is with stock cars. After very substantial modifications, the specs of Mr.Tolan's GS are approaching the Z-28:
Probably his car is roughly competitive with some V-8 Camaro with auto transmission. With older ones in bad shape. Or if the driver have no experience with manual shift. But definitely not so fast as the current SS with a good driver.