i just lowered my tc a week ago and i've been driving on it pretty good so far...but a couple of times i hear scratches underneath my car but its not from the bumper...i think its the pipe under my car or the exhaust or something, i dont know what it is, has anybody had this problem and what did you do or what should i do to fix / prevent it?

 

I had that problem before, the roads in San Francisco are really bad. I just try to aviod bumps and steep driveways.