High flow cat woes

[OyvindRX]

Found a used RE-Amemiya cat on one of the famous auction sites abroad, it looks very nice/little used on the outside, however, on the picture of the inside (most likely the "clean" side) there is a black portion. Now as I have limited experience with HF cats, it does seem like maybe there has been a big oil leak on the exhaust side that has seeped down. Now, I have a theory that if it's to be mounted and driven up to temp, it might get cleaned off, or would you judge this as junk?

See the picture for what I'm referring to.

 

[jack.am]

As long as it's not rattling the substrate is probably fine. They do tend to spontaneously shoot their guts all over the road though.

 

[Jake_rorx7]

This will probably burn off no problem

 

[OyvindRX]

Lets hope so, because I pulled the trigger and bought it
Worst case, buy an HJS cat and weld it in.