http://www.e90post.com/forums/forumdisplay.php?f=16
Also there is a maintenance sub forum and a lot of other stuff in the subforum directory
above and there are more sub forums on the top level it takes a while to
find your way around here.
http://www.e90post.com/forums/index.php?
You have to take a lot of stuff off the two plugs in the back look like a reach.
You need to use a torque wrench . I get the impression from reading the posts
the the NGK's are better than the Bosches.