It's not too bad, just fiddly as access is tight, photo in this thread >>>
https://www.e90post.com/forums/showp...65&postcount=4
After cleaning the boost sensor it wasn't any faster, but felt smoother & more responsive, it also felt better on cold start as it was always a bit lumpy, despite no glow plug issues.
Regarding the EGR, 'assuming' it does do something during the regen, then as it rarely moves it will have got gunked up and caused it to stick again would be the logical conclusion, easy to check that though without having to remove it.