Engine oil MOTUL or FUCHS

Other Euro brands such as Castrol or Motul are also fine choices

I used Motul and it made shifting noticeably better

I used the Kawasaki 10w-40 for the first year I rode mine, it would always have an odd mis shift here and there. Last year I used Motul 7100 and it made a huge difference, way less shifting issues

If you are considering an oil additive, best practice is to instead use higher quality oil (I like motul) and select one which matches your use case.

Been running Fuchs 5W40 lately, N52 with 130k kms

I use Fuchs Titan SuperSyn 5W-40 - widely considered to be the lowest-consumption oil for the M54 engine, and it's very cheap.

Mann filter.

I've been using Motul for hybrid cars.

Well after the second oil change in the dealer I decided to look a external place to change my VN oil but I just bring everything and since then I use Motul 5w-30, no issues so far, a bit expensive but I dont care.

Motul 5100 because it makes the gearshift feel nice.

I've posted my UOAs on TDIClub and BITOG. The factory fill was additive depleted at 5400 miles. The Fuchs 507.00 in the next fill was good for 7-7500 miles. It might have gone longer, but I changed it out in advance of a long trip. Bottom line is that preliminary evidence is that the 507 oils are inadequate for extended OCIs in the 3.0L motor.