I bought this car with a big ol' hole in the exhaust piping, so I opted to get some 2.24" mandrel-bent catback with a n1 muffler.. I never noticed it with my silencer on it, but without it there is popping sounds as I let off the gas.. never knew if this was normal.

I looked into backfiring and it sounds similar, but I have good plug wires, plugs, and no black smoke coming out of my exhaust, so i'm not running rich. So whatever it is, I hope its just normal with my exhaust setup.

 

car running lean possibly because of bigger piping.