MY BUDDIE HAS AN 03 COBRA WITH A BASSANI X-PIPE,MAC 3INCH CAT BACK AND 3 1/2 INCH TIPS,,I LIKE THE SOUND BUT I THINK I MIGHT GO WITH THE 2 AND A HALF CAT BACK,,SO MY QUESTION IS WILL THE HALF INCH MAKE A DIFFERENCE IN SOUND OR WILL IT EFFECT THE HORSEPOWER GAINS ,THE REASON BEING IS HIS CAR IS A LITTLE LOUD FOR MY TASTE

 

just go with the 3".. not difference, but it will sound deeper, and deeper is better[:@]