Louder engine noise and more vibration after Exhaust header change

[midnite86]

Hello guys,
I have a problem with my toyota gt86 and I hope you can help me.

In February i replaced my aftermarket uel catless Header with the original Toyota GT86 header for legal reasons. Unfortunately i wasnt able to fit it in properly as some original screws were missing and i had an aftermarket overpipe which might also not fit in perfectly with the original header but im not sure about that and couldnt test it as my original overpipe was damaged in the process of replacing it with the aftermarket header. As a result my car was having an massive exhaust leak from the right front wheel area so i brought my car to a shop so that they can fix the leak, as i wasnt capable of doing it myself. (Together with the header change i also changed my engine oil and oil filter.)

The leak seemed to be fixed afterwards but ever since my engine (not the exhaust sound) seems to be much louder and vibrating more aswell. For example when revin my car at over 2,5-3k rpm it seemed much louder than it should and was before the header change and it sounded unhealthy when revving even higher. Now i rly want to fix this problem but idk where to start. Could it be the original header not being 100% compatible with the aftermarket overpipe? could it be that there is still a leak somewhere else thats causing this even though the exhaust sound comes as it should and its only the engine noise that is so loud? I also have an OFT Tablet with which i optimised my software to the uel header and now changed it back to the original tune.
I would rly appreciate every tip or solution you have for me!

thank you in advance!

[Turdinator]

Hello and welcome to the forums. Could you post a video of the noise it makes?