Do I need new clamps or hangers to install this?

The system bolts to your factory catalytic converter flange. You'll need to confirm that existing exhaust hangers and clamps align with this catback design — test-fit before final tightening.

Will this bolt straight to my stock cat, or do I need an adapter?

This catback is designed to bolt directly to the factory catalytic converter. No adapter needed if your cat is in stock condition.

Does this come with a resonator or muffler?

You're getting the complete catback assembly — piping and muffler from cat back. If you want to see what resonator or tip options are available, reach out; fitment varies based on configuration.