I finally got under the car to figure out where the exhaust leak was. the leak was at the rear flange right before the muffler. so my great plan was to just delete the muffler and run a straight pipe and I actually really like the exhaust note of the 5 cylinder. well my question is.. what is the spring / blowoff looking thing on the top of the oem muffler?

 

our oem muffler is a variable flow muffler. that spring is probably what control a flap inside the muffler to open wider when more exhaust is push through the

 

^ Correct! By removing the muffler you also lose back pressure.