Will this work with my factory catalytic converter?

Yes. This catback system bolts directly to your existing catalytic converter. The factory converter stays in place—you're only replacing the exhaust from that point back.

What mounting hardware comes with this?

The system assembly is included. Confirm all fasteners are present before installation; you may need to source additional hardware or hangers depending on your vehicle's condition.

Do I need to get this welded or can I bolt it on myself?

This bolts on. No welding required. Basic hand tools and jack stands are all you need—plan on a couple of hours if you're doing it in a driveway.