Thanks much. I'm actually using a set of MAK's to get from a pair of GESi cats to a Corsa Sport.Driver's side manifold is welded to the cat, you'd have to cut it (ala MAK Cat Deletes) and weld a flange in. Based on the pictures below, I'd say a 3 inch Vibrant 2-Bolt Flange would be appropriate. Read the MAK instructions at the link below and it will give you more info as the cat inlet is not perfectly round and may need some hammering to round it out after cutting. The lower pipe after the cats is definitely 2.5" fyi. Necks down to a bit less than 2.25" at the resonator inlet and back up to 2.5" after the resonator on both sides. The passenger side is flanged between the manifold and cat and also at the resonator inlet so that side is removeable.
MAK Cat Delete Instructions: https://www.makperformance.com/assets/images/Instructions/Ford 2015 Mustang Cat Delete Pipes.pdf
They're not installed yet but they will be flanged to the OEM header both sides. The MAK delete pipes will get cut and welded at the cat end to take into account the shorter length needed. Still debating a flex section or two. Hopefully will get a decent gain without LT's as I wanted to avoid the testing hassles in the Chicago smog zone.
