Do I need matching V-band flanges to use this clamp?

Yes. This clamp works only with V-band flanges welded or bolted to your piping. The flange profile must match the clamp design for a proper seal.

Can I reuse this clamp if I disconnect it?

Absolutely. The whole point of V-band design is quick disconnect and reconnect. You can separate and reseal it as many times as you need without degrading the seal.

Will this clamp handle high-temperature exhaust without loosening?

Stainless steel holds up to heat cycles well, but you'll need to periodically check the band tension—exhaust systems expand and contract, and clamps can gradually loosen over time. A quick retighten during routine maintenance keeps the seal tight.