Hmmm....you realize Castrol Edge is MB229.3 approved whereas Mobil 1 meets MB229.5 specifications. Porsche recommends 229.5 oils. If there is no reason to switch, why go against what Porsche recommends?

 

Castrol actually makes a bold claim; 8 times better wear protection than mobile 1. http://www.castroledgeusa.com/

 

Let's discuss...

 

Over thinking this issue. Frequency is the key! OK, tell me who is leaving oil in the car for more than 5000 miles? If so, be careful especially in the summer months and hot environments.

 

That's all marketing mumbo jumbo but it works. Your respected German tuner is probably a Castrol distributor who is getting paid by Castrol. Look at the MB (Mercedes Benz) specification of Castro Edge. It clearly states 229.3. All higher end MB AMGs require oil that meets 229.5. That said, I agree with Robert, frequency is the key.

 

If I were mobile I would sue their **** off, should it not be true or provable.

 

Hah! Mobil 1 did sue them a few years back for their marketing of "synthetic" oil. Castro was using a cheper base stock (not PAO) and calling it "synthetic". Mobil 1 lost because the definition of "synthetic" is pretty broad.

 

I went to a seminar once with some Lotus engineers that designed and tested the LT5 engine in the 1990 thru 1995 (15 years ago) Corvette ZR1's. This question came up and one of the Lotus engineers said " No motor oil to his knowledge has been tested to the extremes with repeated, consistant, results that greatly exceeded all thier expectations. Why would you even consider using something else?" Da!

 

The true test is to do the following:

Get mobil 1, change oil and run for 2000 miles.
Get other oil, change oil and run for 2000 miles.

Compare t he two arainst a quart that you kept and see which one worked out better for you.