I may, haven't decided yet.

Heres the website address for the article on drain intervals.

http://www.amsoil.com/lit/lng_article/march_lng_new.pdf

Last year I did the one year thing on both my car and my wife's car ('00 Tracer with SOHC 2L). I used Amsoil's standard synthetic. Both cars went about 20K. Neither car dropped more than 1/2 quart of oil in that time. I think that's a measure of the oil's volatility as much as anything.

I haven't been as confident with Mobil 1 on the extended drain, because Mobil doesn't talk about it. I still don't think they are formulating for the very extended drain cycle that Amsoil does. I think that Amsoil really works hard on keeping the volatility low, Mobil has different priorities.

I was looking at some Amsoil stuff. With proper filtration, the drain interval the large Diesels are doing is mind-boggling. Just saw one where a guy has his oil analyzed regularly, and changes it as needed. Last change was 409,000 (yes, that's correct ) miles ago, and the oil still meets spec.

A few years ago I remember having a conversation I had with a Dr. friend who had just bought new car. (Honda-Isuzu SUV actually.) He noticed that the oil drain interval in the owners manual was much longer than the 3K he had been hearing all around. This guys pretty sharp. He graduated Cum Alude with a degree in engineering before deciding to go med school - at the Mayo clinic. I just asked him what benefit would Honda-Isuzu have in recommending a longer drain interval than necessary toprovide for maximum engine longevity? What benefit would there be for the oil manufacturers, and engine lube places, to recommend shorter than necessary intervals? So who is probably more accurate? For him the light went on immediately.

With garden variety dino lube, Ford recommends 5K.

Food for thought.
Richard