Do I need to weld these pipes together, or do they connect some other way?

These are straight sections meant for welding. You'll need access to a welder and basic fabrication skills—or a shop to assemble them. No slip-fit or clamp connections included.

Will these pipes rust if I don't paint or coat them?

Mild steel will oxidize and rust over time when exposed to moisture and exhaust heat. Plan to strip, weld, then prime and paint the finished assembly before installation, or apply heat-resistant coating.

What diameter are these pipes, and will they fit standard exhaust flanges?

These are 2" diameter tubes. Compatibility with your flanges and mufflers depends on your specific setup—measure your current or target components before ordering to confirm fit.