I don't think the differences between LM and the oils edy mentioned result in much real world wear and deposits differences. The numbers are better, as he described but if you like LM, keep using it. Even the Molygen. A UOA every so often will keep you informed as to how the 1.8T is doing.
Today I drove across Alligator Alley from Miami to Naples again, approximately 150 miles each way. For the very first time i could feel a difference between the x20 vs the x40. The turbo was very sluggish and gave me very little power below 3500RPM. It was very noticeable and disconcerting. I'm not sure how the different oil pump would cause this since the car was up to temperature and the cruise was at an average speed of 60mph but it's there. I may move to an x30. During acceleration from lower RPM, the x20, in my car at least, was excessively noisy regardless of brand. I firmly believe an x20 is fine in vehicles designed around it but like edy states, this isn't one of those. But throw in the wrench of an oil pump designed to flow lower viscosity better than a heavier, increased HTHS one...and you have this result. Like ARCO has opined previously, a 30 weight might be the sweet spot. I'm no longer concerned with meeting VW LL approval, my baseline is an oil I can run 5k miles that returns good UOA.