Subaru EJ253 AVLS. Part 1 - How it works.

This will be a 3 or 4 part series on how to hack the AVLS system on 2006+ Naturally-Aspirated EJ series Subaru motors in order to install the engine into a pre-2006 vehicle.
NOTE: This is NOT a step-by-step instructional on the install of the motor itself, but merely a description of how the AVLS system works and how to modify it so that these newer AVLS motors can be installed in older Subarus.