Cheers Mates!
Today's beer of choice is Budweiser - the Czech Lager.
Ok where did we end up last time? Oh yes - after overhauled differential and gearbox have been sorted and installed the workshop also finally got my refurbished steering unit back and had it put into the car again. Only problem was however whilst spending some (4-6?) weeks in the workshop the radiator miraculously decided to reveal some leakage. Given that temperature is a thing with this Sierra (i reckon its a matter concerning 2WDs in general but as mentioned mine got freaking hot even after very gentle 30 kms on the Autobahn) I started to look for a new radiator and some other anciliary things. Result was new 4x4 header Tank incl. Roose Motorsport hoses, Graham Goode cooling pipes, some temperature sensors, pro alloy satin black radiator & fans, MSD Fan Loom, and new water pump (also GGR). Being sort of a victim when shopping online I also got myself Oil Filters, Fuel Filters, new HD ignition leads, plugs and distributor cap as I thought the buckling under full load could be a matter of the ignition (more on that later).
Then some more weeks later (car mechs keep on telling you they are always busiy dont they? My assumption would have been that once you got a cossie to fix, all other work ranks below but somehow they didnt share my view) I was able to pick the old thing up!
Temparature was under control, fans were running (even in the right direction i.e. sucking air through the radiator unit), steering was working and gearbox was A LOT quieter. Also the problems under load are now solved despite the fact that ignition related stuff I bought had not been installed (yet). Apparently this was more a boost related issue and after adjusting the boost via the actuator the car now builds up boost smoothly and holds it at 0.6 bar (8.7 psi ?). The car is supposed to be stock so I guess thats about rightish (dont know how accurate the VDO boost gauge is the previous owner had installed). Is everything fine now? Heck no! When lifting the throttle pedal there are still some noises coming from the front end of the car, the coating is shite and needs full respray, interior needs full makeover but I think next up will be wheels, suspension and related things. So stay tuned if you want.
- how much cleaning does you engine bay need? - Yes!
Close to show-room concours already 
Steering unit looks cleanish-ok to me
So thats basically it for the update - I must say when I drove the car back home that day it was the FIRST TIME I drove it with more joy than fear (engine explodes, steering stops working during drive, gearbox explodes, rear diff dissolves accross the street, etc.) and I loved it. That really got me the motivation I need once in a while to keep on throwing money at this old piece of scrap metal!
Cheers