I am trying to figure out what to use to connect my downpipe to the rest of the exaust. I was thinking of useing the stock flange and ceramic doughnut gasket but i think thats only 2.25" . HIgh flow cats have a 2.5" flange after the cat but there the kind that uses a crush gasket. I would like to find a flange i can use with a 2.5" downpipe. Preferably the donut gasket type so it will be flexable at that joint, but i mite use a standard 2 or3 bolt flat faced 2.5" flange or maby a 2.5" v-band and clamp.