You need not get anything expensive. For instance, older Civics can be picked up REALLY cheap, are quite reliable, are easy to work on, and offer the possibility of a VX swap.

Check rockauto.com for your O2 sensors. half the price stated above. they have good service in my experience and aren't an anonymous internet junk seller.

I doubt you first enter overdrive at 65 mph....thats ridiculous. My cressida locks the torque converter in OD under 45 mph!

Right now Subaru only offers AWD boxer engined vehicles.

That's about what I expected, I'm just going what I see going on with the tach. When it locks up the speedo and tach should move together (not the same rate but the reaction time) right?

Up to 60 there's a swell in the tach with acceleration, you can see it slip. Maybe clean tranny fluid would change that a bit, but tankfulls seem to back it up. A 1.5mpg increase going from 45 to 65 when I know this ain't no basjoos uber-aero indicates an in-effeceincy at 45, not an effceincy at 65.

right?:(

tonight on the way to work I'll try to pay more attention to the tach at different speeds.

That link looks great, I knew there had to be someplace cheaper!

Is there anyway to un-AWD or make it selectable on a Subie?

I've heard of subaru guys pulling driveshafts to make it 2wd but the mechanics of the transmission are still there... it's only half an answer. Find a subaru forum?

The efiiciency difference between 45-65 probably isn't aero. My guess would be that the engine's sweet spot in revs is closer to the rpm at 65. (fuel used to generate X hp at X rpm) OR the TC really isn't locking up till over 45 mph.

you're checking for lockup right, I can't argue there. see above maintenance suggestions.