How do you get to that bastard with the arrow ;-) I can remove the top and bottom of the hose but that third connection has one of those BMW press on both sides to unclip and I can barely wedge my hands in there to begin with - forget pressing this thing off. Will it be better from the wheel well if I remove the fender liner ? should I remove other stuff to give myself access ? I cannot find any good info - trying to get to the chain tensioner to replace it as it's weak (chain and guides were inspected and are fine)

 

I'll answer my own question (and extend into tensioner replacement). There's no magic, it just sucks. A long flat screwdriver and a flashlight for aiming, slowly poking at the ring got it disconnected. Possibly not in its original shape but no way 2 hands went down there. You could imagine right then plugging it back on would be a delight as well.

This time I gave myself more room by unscrewing the airbox and moving it out of the way a bit. Once the air intake hose from hell popped off (it's the 3rd connection that is new to N16 engines that is the fun bit) I still could not extract the tensioner. The throttle body had to go. $%$#%$#%#.
3 more delightful torx screws with no access for normal torx screwdrivers, so some arrangement of sockets/extensions, and my lower back screaming at me, that popped off...Dirty inside... No longer. Also tons of fun to screw back later on 1/4 turn at the time. Pulled all hoses out of the way, and the tensioner came out like butter. Way too much so in fact. I suspect the job was done once before and not tightened well. It would explain the newish looking guides. That also explain oily residue all around...



If I am honest the old tensioner did not feel *that* weak. A tad weaker than the new, but 5mm shorter maybe ? The new one came from detroit tuned as a good replacement for the N16 - not overly strong but longer. Slid right in without undue effort. Tightened hard and checked for leaks later, nope. Had all the predicted fun reattaching the screws of the TB and the clip for the small plastic hose connecting under the rubber air intake hose. Seems looser than before but the hell with it. If it falls off - I definitely know where to find it now !

Turned the car on cold, which previously has a little clatter remaining - nothing terrible but enough to remind me to do something. No codes, and no noise AT ALL. Even the noise I thought was injectors before was gone, so clearly the tensoner could use a little refreshing. Gonna call this a victory - not for my back though.
I had the valve cover off previously at a specialist to double check guides and some oil in a plug well, the guides looked very good, not broken not worn and no timing codes either. So I figured maybe the tensioner would handle the leftover little ticking, it did !
Bleepinghose though !!!