Weird noise comes from my rear-right of the car (it only started happening when I got my DC Sports cat installed...). Also this sound comes when its wet outside, kind of a rubbing noise. Quite possibly grinding against something?

 

jack up the rear of your car and make sure its not hitting your bumper, or your gas tank, or anything for that matter.

 

Hmm but this noise only happens when its raining...i.e my car is wet, so maybe its the water on the exhaust muffler or mid pipe thats affecting it?

 

Maybe its just the rubber supports for your hangers-when rubber is clean, it squeeks when it rubs metals. I think the same thing that happens when you lower your car. It can posibbly be a heat shield. Just guessing...

 

yeah it could be the wet rubber hangers making this noise.