Looking at doing long tubes and a mid pipe (h pipe or prochamber) on my Cobra. The car is tuned with a Posi Race Port, 2.76 Pulley, SCT 2600, KB BAP, 60# Injectors and just a catback. Will this need retuned or can I atleast drive it around for awhile before I go to the dyno? Also, what gains can I expect from swapping it out? Thanks!