If you have a car whose specs is covered by GC, that would be my choice. What the heck do I know though? I've said it before, all I can really offer the board is personal experience and observational analysis. I don't do a lot of technical research, but research word-of-mouth, retail and application issues, etc.
A post like this is bound to polarize members. A technical product backed by reputation and quality composition verses a dubious reputation, difficult-to-obtain mystery oil that is distinguished by esoterics like smell, colour and mind-bending bottle variations.
I am still mostly impartial with brands, Mobil 1 SUV is the first oil I recommend, but I really like GC because nobody else has it. Am I insane? My Audi came filled with it from the factory... am I still insane?
almost forgot, the original poster...see if your friend will do 2x a year changes, then he can just use a normal 30 weight Mobil 1. If he really wants to go a year, Mobil 1 SUV offers a great oil for the money, unless you can find GC at a good price. Sticking with 1 product is important to me, Mobil 1 offers this most easily. That is what I would tell your friend, pick one oil and stick with it. Mobil does not require the stocking-up in advance of GC nor the percieved hassle of ordering Amsoil. If he is not into oil changing, those 2 options sound unlikely anyway. The most likely one he will stick with is 30 weight Mobil 1, although SUV might be a better oil, esp for the long run.
See? A technical analysis might not yield the best answer for the guy. The retail availability of Mobil 1 30 weight and the pattern of service he is likely to follow, results in a different, yet valid, answer than a rigid technical analysis of the oil specs.
[ June 14, 2004, 11:20 PM: Message edited by: Audi Junkie ]