The MPE is fabulous, but it's not going to give you much on lower RPMs. It really comes alive over 4000, especially under load (accelerating, not just revving). You get a bit of nice rumble at idle but I've heard others with more.
Don't figure on turning in your lease w it. Keep your OEM exhaust and put it back on for return, and sell your performance exhaust, whatever you get, and save much of your investment.