First:
My mates shop was unavailable today (family crisis) so I'll get in there tomarra. So I spent better part of the morning doing eyeball diagnostics.
Paperclip test:
If my car was of the later type that would need the box: would the paperclip test not give any codes? "TheBoys" guide to this trick indicated that later models need the real thingie to get actual data.
All I got was 1-2. Thinking that it's all clear.
Symptom update:
The studdering is now so bad that even in the garage (+15C) it's acting up. No need to drive it outside.

Since the the temp factor now is void: leaning strongly towards fuel and/or air distribution issues.
MkI EyeBall checkup:
Talked to former owner (close m8 of mine): he suggested that I check the fuel return lines. He had them changed at a shop. Looking them over I noticed that #5 (counting from front) injector-to-injector hop was still the original one. Prolly a lazy ass mech didnt arse himself to disasemble the in the way parts.
Tho no noticable hardening or cracking was found. Same with main lines. Went out and got some replacement tube to be on the safe side. Putting em in as well on Sunday.
Current fuel filter is... odd. The supposed screw cap at the bottom is not there. Wasn't abel to get close up view. Suspecting some b-rate part there.
Coolant fluid is really murky. No clear rust thank god. It's getting changed tomarra. Gona use a standard coolant flush agent in the shop.
Generator belt is now marked up as "need to change". Side tearing visible. Right type of stiffness felt using the hand test.
Oil leakage at about 1-2 drops / 12h on ground. Automaticly thinking it's related to turbo leak. See more below. Giving the oil system cleaning agent treatment as well.
Side notes...
Turbo issue:
Ok, so I did mention that the turbine is whining. Duly noted and planned for next month service. Looked over the hoses running to-and-from. Most parts thikly coverd in "oily sticku gunk". Clearly high presure oil spray from each seal. It's on most adjacent aparts around. The previously mentioned oil leak issue I chalk up to this.
http://i28.photobucket.com/albums/c247/telluscitizen/OmegaGot both the replacement tubine and that upper part (right under the "Disel Turbo" plastic cover) used parts from old running wreck.
Permited all the parts are 100%; is there any real difficulty in making the swap on this engine? No special tricks or tools needed? (Done a few on other brands). Are there good economical choices for 3rd party tubines or possible other upgrades? Keep in mind my O's a tool for work and I rack up loads of km's /year. Durability and economics are key.