You probably thought it had better throttle response because it was louder...its a common thing. Louder always SEEMS faster...but it isn't. I thought I gained for real at least 15 horsepower cutting the muffler off of my Cobalt...but in fact...it gained nothing. LOL

If your going to remove the resonator...at least take the cat and U-Bend out too and put a glasspack in place of the resonator. A 28" Thrush or Cherry Bomb will work just fine.