I've been using Mobil 1 10W-30 back before it was called SuperSyn, TriSynthetic, etc. Never had any problems with it. The way I look at it is this...

1. The specs on the oil tell me it's a good oil, and that it will protect the engine during the entire driving spectrum that the car will be subjected to.

2. I'm going to change the oil out at 3000 miles anyway, so before the oil can start to break down and not do it's job correctly, it's drained out of the pan.

3. The cost of the oil I'm using is relatively cheap compared to most other things I'm going to do to the car.

I guess the bottom line is, there are many oils that fall in roughly the same performance/protection/properties as Mobil 1. Use what you want at this protection level. The main thing is to be sure to change the oil (duh) at the appropriate time/mileage intervals, and use the correct weight settings for your driving application. Happy .

 

I am using Amsoil, and it works great. Also have it in the rear diff.

 

I am on Amsoil 10W 30 and really don't see much of a difference compared to when I was on Castrol GTX 10W 30.

With the Amsoil, my MPG has decreased though. I am not sure if it is the cooler temps, change in tires, or the oil itself responsible for the decreased fuel economy.

 

To answer my own question - had a long talk with Eddie Farrow, SM at JCH- convinced me that:

a) regular non-synthetic oil is fine for normal use - don't need the expensive stuff if you're not racing the S

b) Owners' Manual statement to change @ 7500 mi is minimum required to maintain warranty. Should be changed between 3-4k. "There'e no such thing as over-maintenance"

c) I'm convinced