nearly all the e300 around 12 of them from what I went and checked the speakers were blown

Exactly why I didn't want to get stock speakers again.

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I bought these spacers from Amazon US and we used them on both rear doors for aftermarket speakers.

https://www.amazon.com/gp/product/B07NZ64D2M/

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Did your stock speakers not come with the bracket already installed or did they just sell you the speaker?