Cobb DP to Megan CBE

I've been searching and can't find the info I need.

I have a Cobb DP (2.5") and a Megan CBE (3.0"). They're currently connected to each other with the stock donut gasket. It's holding up for now, but it just feels "wrong". Is this the correct way to do this or is there some type of adapter to make it proper?

This is backwards from all the other info I've read in which everyone has a 3" DP and is going smaller. I have a 2.5" DP and I'm going bigger.

I guess I was doing the wrong searches:

Here's the excerpted advice from a tech from Megan Racing:

 

Since you have the Cobb downpipe I would recommend you double check for leaks at the junction to the downpipe. The Cobb downpipe is designed to be used with the stock donut gasket while the MR catback is designed to seal better against the 3" flat flange that is found on virtually every other aftermarket downpipe. They can however be used together successfully. If you have not already done so, remove the donut gasket and purchase some smaller diameter flange head bolts and nuts from your local hardware store. Lightly coat both sides of the MR supplied 3" flat gasket with high temperature automotive silicone sealant and place it, well centered between the Cobb DP and MR CBE. Use your newly purchased hardware to secure the two parts together. If you have been using the donut gasket and stock spring bolts I can almost guarantee that you have been running with a sizable exhaust leak, which would certainly make for a louder exhaust note.

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