ok someone correct me if I'm wrong anywhere, from my understanding a 2.5" JDM header collector is really just 2.5" OD and 2.36" ID. So with that in mind would a 2.5"OD flange of a jdm gt spec header bolt up to a 2.36" ID flange of a regular testpipe. Would I have to get a 2.5" testpipe. Would it be ok to go from any jdm header with a 2.5" collector to a regular testpipe then to a 2.36" regular catback? Or is it really important to get a 2.5" custom catback?

edit: also is a regular catback like a greddy, apexi, etc.. really 2.36" OD or ID?

thanks

sorry if this is confusing.

 

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anyone???

 

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