You're probably pretty close then. GT40X heads aren't huge horsepower and torque makers....nor are any of the other parts you've got listed. The more elaborate the parts, the more elaborate the gains will feel. Your combination of parts is pretty conservative and so too will be your gains. After tuning, you may have very well picked up 20-30rwhp, but in a 3,300lb car, 20-30hp isn't really going to jump out and grab ya.