Robin, have you ever been on any other rollers? Maybe JKM have had theirs recalibrated since your first run way back when. I am aware that DD rollers are supposed to be the most tightly regulated, by the manufacturer - and if JKMs were being "over generous" when initially installed - a subsequent recalibration might have down-corrected their readings. I simply mention this because you seem to be saying that the stage 2 "seems better" - so your butt-dyno is telling you the stage 2 is better, but the RR is telling you the opposite.
....I went on some Dyno-Dynamic rollers at Weston Performance today but in Stock map (202.3 bhp) and with a boost graph which showed spike at 1.2 bar and bad drop off from 2,400 revs. Best to forget my butt-dyno!
And what was your stock readings on JKMs DD rollers?
Engine oil - what brand, type and spec oil do you use? And what is your oil consumption like? Do you religiously keep it topped up to the max by adding small amounts frequently, or do you let the oil get fairly low and then add quite a lot?
....Both!! Usually frequent top-ups but there have been a couple of low fills. VW approved Mobil from my dealer. Consumption was heavy for first few thousand miles but now not so often. I change my oil every 10,000 miles.
Eeek. Mobil oils are not really very good for VAG motors. As with any US orginated oil, whilst it may say "fully synthetic" on the bottle, that simple statement breaches European guidelines. Which is why I will always only ever recommend oils from European manufactures, such as Fuchs, Castrol, Motul, Total, Elf, Pentosyn, and the likes.
Regarding the oil change intervals, it might be worth changing every 5k miles or six months. An extra oil change is much cheaper than the hassle of a new turbo!
Regarding actually finding oil in the turbo discharge pipe, I think this is fairly common. I found oil in mine, and inside the standard intercooler - but it wasnt much. Maybe one or two tablespoons, which is fairly reasonable. However, I wonder if the stock GTI intercooler has something to do with this? I personally reckon the stock i/c is slightly restrictive, which can cause a slight backpressure on the inlet side of the turbo. Since upgrading mine to the S3 cooler and twintercooler, I do notice a much more rapid rise in turbo boost - which prooves that the airflow through the inlet tract is much freer and less restrictive. Maybe this is also having an effect on the way that the oil vapours from the crankcase ventilation system are not getting to the combustion chambers quick enough. Think of having a hot shower in a closed bathroom - the shower will steam away, but if you have a mega powerful extractor fan immediately above the shower head, it will suck out all the steam. However, if you have a clogged, weedy fan, the steam wont get sucked out, but will condense on your bathroom mirror, and then dribble off the bottom edge.
....Sounds like very good justification for a S3 intercooler! My priorities are (1) This turbo issue (2) Suspension due to KoniFSD issue (3) Powdercoat Monzas.
But leaving 2 and 3 for a while wont in any way affect the performance or reliability of the engine. By fitting a larger upgraded intercooler, and used with your existing remap - then the larger cooler should put less stress on the turbo, and actually help the turbo work a little better.
Onto a couple of other issues. Did JKM plug in a VAG-COM to check for fault codes? And did they carefully monitor the N75 cycle?
....Yes and no fault codes seen. Dunno about N75 cycle - What is that?
Answered earlier.
Regarding the actual replacement of the turbo - only you can decide which is the best way. However, I would personally never recommend any second hand turbo, no matter how well the previous owner claimed to have looked after it. You only need to recall some of the threads on the other GTI fourm (revving engines whilst stationary, "blipping" throttles, correct turbo cool down - I even think that you mis-understood about the cool-down procedure), and it simply showed a fundamental lack of knowledge on how to car for an engine in general, let alone the specific requirements of a turbo. If I were forced to only take a 2nd hand turbo, then I would send it to a specialist turbo re-builder for a complete overhall and warranty.
If your original turbo is knackered, I would personally seek a specialist recon, or go for the genuine new VW part. Yes, I understand your POV that the official VW 2 year warranty will probably be void - but it is the "peace of mind" from getting an OEM supplied part - you can pretty much expect an OEM new turbo to last a long while, but how long will a slightly cheaper second hand one last. The labour charges will be the same, but if the 2nd hand one doesn't last, then someone will be paying the labour charges all over again.
....As usual, you make a very good point. If the second-hand K03 costs £400 + £200?? for overhaul = £600 approx and a new VW one costs £650, which to go for? I don't know if it's true but I've heard that VW sell reconditioned turbos.
Thanks as always for your time and valuable input 
Yup, VW officially supply guaranteed reconditioned units, which include engines, starter motors, and tubos. As others have stated, the part number will end in an "X" (meaning eXchange) for a reconditioned unit. These parts are re-manufactured to the same identical tollerances and specs as brand new units. Furthermore, in some instances, even if you order an exchanged component, you sometimes will still get a brand new item, but still pay the cheaper exchange price!
Happy to help when I can.
