STS system is very appealing, but remember all that piping going from the back of the car to the front has to be pressurized. Even if you had the fasting spooling turbos ever, you've still got a LOT of piping (& intercooler/s) to pressurize.
It certainly is appealing for ease of install (at least on the C6 compared to traditional TT setups), and thus cost of install if you're not doing it yourself, keeping the heat out of the engine bay & headders/manifolds. But it is not the best setup from a pure performance only standpoint.
I dont know if SC cars suffer as badly from hot weather as turbos do, but after owning 4 turbocharged cars and going to a C5 vette I dont think I would ever turbo an already powerful NA car. I'd either go all motor or maybe SC next time around. I just dont like the turbo side effects after living with them for so many years.
That being said, I do miss the sudden crazy on boost power spike of a modded turbo setup with a lot of boost & power. Sure it's not practical, but gawd is it a lot of fun!!!