Anyone uses this exhaust ? I'm pretty sure it will fit the 550 but the question is, will it affect the engine performance ? It appears this is designed for the 6cyl not 8. I know Umnitza has a similar one that works on all 6 and 8cyl e60, and this one seems to be a clone of Umnitza but much cheaper.

https://www.ebay.com/itm/282407956284