So I know the recommended is the Castrol 10w60 same as the BMW M series etc .
Has anyone used the Redline 10W60 . I found a source for 5 gallon pails , very reasonable cost compared to the costly Castrol liquid gold .

 

I would say go with Castrol's synthetic oils as they are recommended by many manufacturers and mechanics. Formerly known as Castrol Syntec, the new Castrol Edge with SPT (Syntec Power Technology) is one of the best synthetic engine oils for the money. This oil features long drain intervals and excellent protection against metal-on-metal wear, making it a great choice for drivers who rack up miles quickly.

 

If I recall correctly, a few people have used non-Castrol oils to no ill effect. I honestly don't think it'd make a difference (especially under normal driving) so long as the oil specs match factory requirements. A lot of owners are very picky about this, but like many other things with our cars - I doubt it'd have a real effect on your car. There are some things where it does matter - gear oil in an ASM transmission, for example. But in my opinion, you should be fine with Redline in your engine.

Last year I did a bunch of research into competing oils. In some places the Castrol does outperform the others. It's been a while since I've looked at all the resources I gathered but, as best as I can remember, I didn't see a performance-based reason to switch - Redline, Royal Purple, etc, didn't outperform the Castrol oil in a way that made me want to change oils. I think the only time I saw a notable difference was with Amsoil - but they also sponsored that test (testing was performed by an independent lab and they offered up everything involved to back the results).

For the vast majority of AM owners, there won't be an appreciable difference between oils.