driveshaft angles measured
 

Also while I was under the car this weekend, I measured the angles between each section of the driveshaft. Relative to the pinion shaft in the rear diff, the engine is tilted about 4 degrees back (yes the engine really is tilted back). The angle of the front section of the driveshaft appears to be designed to be at zero degrees tilt relative to the engine. Then it looks like the angle between the front and rear sections of the driveshaft are designed to be at about 2 degrees. The angle between the rear section of the driveshaft and the pinion shaft in the rear diff appears to be designed to be at 2 degrees.

The equal angles at two successive u-joints represent the classic design to cancel varying angular velocity caused by a angled u-joint. So, it looks like Subaru did their homework. Anyhow, for those of you who have read up on driveline theory, I thought you might find this interesting.

Mychailo,
We're going to have to have a talk with your fiance...she's obviously doesn't have any idea of how you're spending your time on weekends:D :D
Thanks for the interesting info. So, how does this factor in with your custom driveshaft efforts?
-Bill

With the equal angles, this means that the best driveshaft for the car is not the one with the CV joint in the center, but the one with a u-joint in the center. For the 5MT people, I think its important to make sure that all the angles are correct after the 5MT swap. The angles were off a little bit for mine even though it appeared that the engine was at the same tilt as before the 5MT swap. I was able to equalized the angles by shimming the carrier bearing with two thick washers to drop the carrier bearing down a little bit. Alternatively, I could have shimmed the rear transmission to bring it up a little bit. The carrier bearing was easier, so I took that option.