Do I need to remove the catalytic converter to install this?

No. This catback system bolts directly to the converter outlet. Your existing converter stays in place. You're only swapping everything downstream from that connection point.

Will this require welding or does it bolt on completely?

Bolt-on throughout. No cutting or welding needed. Installation uses factory mounting points on the 4-door chassis.

Should I get this ceramic-coated or painted before installation?

Stainless steel doesn't require coating or paint — that's the material advantage. It weathers naturally and resists discoloration. Install as-is and monitor for any minor surface patina over time.