So I was driving the car and everything seemed fine. I stopped to get a hair cut and found it odd that my car stalled on me for no reason as I was parking. Started right up no problems.

Came back out and a buddy wanted to hear my exhaust (Fabspeed x pipe w/ test pipes). I got it to about 6-7k gradually. Now it sounds like my exhaust has a hole in it. A lot of vibrations coming from the rear and almost seems like a cylinder is misfiring. Sounds very droney.

The car runs normal but does seem a little weaker than normal, and as I come to a rolling stop the car backfires in a crisp loud BANG frequently. No check engine light.

I did a quick look over the exhaust and it looks fine. Thoughts, input? This is an 04, Manual.

Thanks in advance!

How old are the plugs in terms of mileage?

Plugs are about 8000 miles on them.

Any check engine lights?

Nope. I'm thinking about just replacing the plugs, even if it doesn't fix it, for $85 it wont hurt. Heard good things about the NGK PFR7G-11S Laser Platinum plugs.