I had a "stage II" port completed over the past winter and the TB flange was only opened up to the factory o-ring. With a Soler Performance ported TB (91mm effective) the car picked up almost +6mph in the 1/4 mile trapping a best of 129.27mph three weeks ago. This equates to about that 50-60hp number that you'll read on the internet. The car also pulls the wheels on the launch which was icing on the cake! I was truly shocked! I have stock heads and cam btw.
I am completely sold on the value of SC porting! It has literally changed how responsive the car is, it's amazing, All I can recommend is "do it"