Okay I just installed my VS with 3.3 pulley, 3 inch DP with No cat, No res. 2.5 inch pipes back to stock Y and stock Mufflers, SSAC Headers 104's and drilled 180 t-stat. HOLY SH!!!T IT SCREAMS. I'm very happy with the results. I have a custom tune from Big worm's performance shop. One of his GTP's runs mid 13's and mine is Clearly faster from any roll or a dig. I can't wait to get to the track and see what it does!