Will this work with a diesel particulate filter (DPF)?

Yes. This is a filter-back system, meaning it connects downstream of the DPF. Your emissions equipment stays intact and functional.

Do I need to remove the factory exhaust completely?

Unbolt the stock system from the filter housing back. The new stainless assembly bolts in at the same factory connection points—no adaptation needed.

Will stainless steel hold up to diesel exhaust heat and soot?

Stainless is corrosion-resistant, which matters for diesel engines that run soot and condensation through the system. It resists rust and scale buildup better than mild steel.