I completed this job recently. Honestly, it wasn't that bad except I broke those hoses that are in the front of the intake. They were brittle and just shattered as I was pulling them off. I had replacements ready though.

I think this job is far easier than replacing the brake booster / master cylinder. Getting those brake lines threaded back in was an absolute bastard.

I think I could easily do the whole thing in a day. A good set of universal socket joints is the key to getting the intake manifold bolts off.

Also be sure to use a torque wrench so as not to over-tighten your replacement cap seal (valley pan cover).

I found the guide referenced in this thread to be very useful https://www.bimmerfest.com/forums/sh...d.php?t=525719

It's for a 645 but many of the steps are the same.