we have done this in the past with both the GTP, and the LSJ supercharged cobalts. mixed reviews really, but ill tell you that both cars were substantially faster after pulling the blower off. i have driven several twin charged cobalts that made north of 500 WHP, and was not terribly impressed (compared to a strictly turbo only setup). its really hard on parts, overly complex, and just generally works better on paper than it does in any practical application.
with an unrestricive intake manifold, and a "good" supercharger, i would expect results to be considerably better than blowing through crappy old gen 3 M90s like we were doing many many moons ago.
my vote: a properly sized turbo, and a tiny shot of the sauce to get you out of the hole
