I'll take the flange any day. I have a few of them 1/2" thick for some mufflers when they don't drop far enough to clear a firewall. Keeping the smoke inlet closer to the the exhaust port by having the inlet in the spacer/flange does produce better smoke than having the inlet farther out on the extended muffler. Bisson mufflers makes them for various versions of their muffler products. Drilled and tapped for a fitting.