Engine oil Mobil or IDEMITSU

I just switched to Mobil 1 for the last interval and the engine ran much better on it.

I used 5w40 Mobil 1 Full Synthetic in my 08 Passat. Had such great results, I carried it over to my 12 R Line.

I did my 1.8T AWP valve cover gasket two weeks ago and I can highly recommend Mobil1 0/40. Used it since 3/2002.

Mobil 1 10w30 with a bosch filter up here in Canada. Haven't had a tick since I started using it, at 110k km my engine is in good shape to begin with though.

the Mobil 1 is the 0w40 Euro Formula, and has the VW502.00 approval that being said, Mobil 1 5w40 Turbo Diesel Truck is also a good choice, but no VW approval.

I'm using Mobil 0w40 (502 spec) in my B5 Passat for 140K and plan to use the same oil for my GLI when the free maintenance ends.

You don't need to add any more additives to modern day oils. You said you will be using Mazda 0W-20 oil? This is one of the best 0W-20 oils on the market. It is made by Idemitsu for Mazda. It has very high Viscosity Index of 221. Most 0W-20 oils are around 170. This means it is one of the lightest 0W-20 at start up. This is what you want in the winter.

I run Mobil 1 5w30 and still change it every 5k. I could probably bump it up to 7500 or 10k but don't because I do it myself, and it isn't a huge cost or inconvenience to do it early.

I run the extended performance Mobil 1 in my Toyotas at 15k mile intervals, with an oil filter change every 5k miles.

10w-40 Mobil 1 is the best oil you can have for your VR6 engine. Besides superior protection it also takes longer for the oil viscosity to break down.