If a 2011-2015 Mitsubishi Outlander comes into the shop with a buzz/squeak/rattle complaint, check the exhaust heat shields. If the shields are touching each other, use a screwdriver or other pry tool to pry them apart so that there is about 4mm clearance. If the noise remains, replace the seal ring, springs and bolts. DO NOT replace the center exhaust pipe with catalytic converter until all other potential causes of the noise have been eliminated.