I have to say the exhaust made a huge difference, one I can feel and that takes 20-30-whp for me to feel. It just screams through the first two gears and have not had a good lace to wring third to redline. Maybe on the interstate. Gas mileage seems tom be better also. My take on this is because I run 50% more boost than stock there is more spent gasses to get out and that Magnaflow with then built in X-pipe is of wonderful design and workmanship with the Borla exiiting out back. It is louder than I would have likes and am not sure a round perforated muffler would fit between the 2 existing mufflers. Perforated mufflers don't lose power and neither do they deaden sound very well. For the power it gained I'll take the sound.
It literally screams and often goes past redline in 1st gear since it revs so quickly! I highly recommend the combo i used. Fairly inexpensive power like adding the 65mm SC pulley. If you don't mind the sound I highly recommend it, Mark