i just installed an invidia g200 exhaust on my o6 coupe im gettin a horrible rattle and vibration from under the passenger seat thats the only side it can be felt but the rattle is horrid anyone know anything of this problem is there a quik fix let me know

 

I had the same problem , so I took it back to the muffler shop that installed it. They heated the pipe and bent it down (away from the car). They did it 2 times to make sure it was bent enough.
That was done over a year and half ago, never had the problem again.