Very interesting link on the Mobil 1 longevity test!
I've always thought 7.5-10K oil changes for synthetics is about right.
Dyno oil has always been thought to break down much quicker, which I also believe.

When I get my HCH-II, I will change the original oil when the car tells me to. After that, I'll probably change it at 7.5K, or sooner if the car tells me to. I think any sooner with a full synthetic is a waste of money. Although, it's not a terribly expensive waste of money, and I have no issue with folks changing it every 3K. I believe changing the filter with EVERY oil change is more important than whether the (full-synthetic) oil is changed out at 3K or 10K.

Steve

STOP terrorism - Drive a HYBRID

Vehicles:
350 miles a week ------------ 2006 HCH II, Magnetic Pearl, w/NAVI (born on May 25, 2006)
350 miles a month ---------- 2003 Mazda Tribute ES-V6
350 miles a year (for now) - 1986 Mercedes 560SL