Well, I gave my ideal system as per bench racing. Logs, downpipes, internal x-pipe muffler up close to the motor, resonator delete and a nice Borla muffler(no drone and good bottom end torque). Nobody else interested in venturing a guess or posting what you have done and the results you have achieved? Another thing is my motor should run 40-45% more than stock boost and have that amount of extra fuel to expel. Almost half again than stock. The stock system has proven good and cutouts for the most part do not offer even a tenth because the users have a good system after where the rear cats would have been making the cutouts not worth a darn. I've held back because 15whp for a $1500. exhaust system is way out of my return on the dollar. maybe the logs will release a bunch of exhaust gasses making the rest of the exhaust mods work like they should and yield the power one would would expct?