Positive: After installation, I definitely noticed an increase in performance from around 2800 rpm. It matched my stock Cat and 2" Cat rear exhaust pretty well. Bad: Had to return the first one due to installation issues. Note that you may have to remove some metal from the power steering rack mount to get the proper clearance. I would also recommend throwing the gaskets that came with the kit in the trash and getting suitable gaskets from your favorite auto parts store. You'll also need to extend the O2 sensor wires (or buy a new sensor, seriously it's an MK1, it might be necessary). Overall I'm very happy with the performance of this header.