New cat also new noise? Mystery please help

2005 Subaru impreza outback sport manual transmission with ~360k total but 30k on engine rebuild. So… was making gnarly cat rattles and had both catalytic converters replaced and boy did it need it but immediately after car now makes terrible rattling almost knocking noise. Sounds like engine knock almost except weirdly is way louder from inside car then from outside with hood open. Makes noise when I give it gas. While Googleing and such I’ve found videos of torque converters gone bad – well it sounds like that except I have a manual transmission. If I’ve been running on a bad cat for a while unknowingly is it possible replacing them has caused my engine to knock? More oxygen?? Helpp! Sounds like from front right wheel well area, but loudest in the driver seat. It’s an awful sounding/feeling noise but also car drives so much better now, the power increase from the terrible clogged up cat being replaced is so so noticeable. I’m both mystified and terrified cus that install wasn’t cheap and now if theres another, more serious problem I’m bout ready to roll her off a cliff…

Can you post a sound clip?

Could it be loose heat shields ?

Or exhaust reinstalled too close to body, frame or any other part of car? When the engine accelerates, the motor mounts allow the engine to move, which in turn moves the exhaust. It may rub on something while accelerating.

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the sound is new? were you so focused on cat rattle before that you did not hear the 2nd sound before? if not than who installed cats? the shop has no opinion on sound?

This sound is new. I think I used to hear a much milder version when I drove only in reverse and specifically reversed uphill. @COROLLAGUY1 here is clip.

Dang it couldnt get it to post. Try again after work

Sort of sounds like an exhaust leak…maybe…

Like someone mentioned above, does the shop that did the exhaust work have an opinion on the noise?

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I’m going to take it back on Tuesday. They left for me to pick it up on Friday evening. So didnt get to chat but I had to drive it even though it felt wrong. I wanted to just leave it there.