I did the RPM Stage 3 to my car this winter. Didn't need to disconnect the motor mounts and jack up the motor to get the stock cat out. Just be patient and twist till it comes out. I opted for the catless, but I'm really questioning that decision, I'm going to make a final decision after I am finally able to drive it around and smell the difference. I've been starting the car in my garage and it does smell like raw exhaust.
Alpine ILX-107 with Rearview Camera
Upgraded RPM Turbo