Love my M perf exhaust. My GF thought it was a huge waste of money when I told her how much it was going to cost me. When my car came in, the techs weren't able to install the exhaust until the next day so I picked the car up and we drove around without the PE.
Got the PE installed on the car the next day. Turned it on and wow. Drove around and lots more *wow*. By the time we got home after the first trip, she had changed her opinion from "waste of money" to "totally worth it".