the other kits are cheap cast iron. Crappy fit on the door/frame, and intake slide. They do let some air in, no matter how far you shut it down. Which ain't always a bad thing.... a little RTV hi-temp silicone can help, but it always ends up peeling off.
The pressed steel Sotz kit does not have a gasket, either. But the way the door fits the bellowed frame lets no air in.
