Do I need new fasteners or clamps to install this?

The axleback mounts directly to factory hanger points and the existing exhaust flange upstream. Verify your OEM fasteners are in good condition before installation; if corroded or stripped, grab fresh hardware from your local parts store.

Will this require a tune or affect engine performance?

This is a bolt-on muffler and tailpipe replacement with minimal flow change. A tune is not required. See your vehicle's service manual or a tuner if you have specific questions about backpressure on your setup.

Can I polish the tip further, or does it need prep before installation?

The tip arrives polished and ready to bolt on—no prep needed. If you want a mirror finish, you can hand-polish it with metal polish and a soft cloth after install, but it's cosmetic only.