The difference is that the GT500's engine is "built" for boost where the LS3 isn't. You would need more than just a blower to compete with the GT500 if you don't want to blow your engine up
The LS3 will handle a blower just fine with a good tune. They are slapping super chargers on factory G8's without any problems and they are performing great. And I know that GTO owners have done the same. There may be a couple of minor things, but its not like you need new crank, pistons, rods.
2011 Synergy Green Metallic 1SS Camaro:
RS Package, White Ralley Stripes, Premium Sound.
Mods; Flowmaster Exhaust, Vararam CAI, Pfadt Sport Suspension, Budnik "Ice" Wheels, Nitto Invo tires
Upcoming Mods; Custom grill and badging.