1. 337 is not needed to install AV-30. It will be covered under AML or STC (not sure which). 2. The STC does not cover vaccum removal. It's up to you to figure this part out. 3. If nothing uses the vaccum system you can file a 337 and remove it. Realistically this won't do much for most of us until the AV-30 drives an autopilot. At least for me, the target is to use the AV-30 to replace the electric turn/slip gyro. Then it's wait-and-see what the autopilot features will be. G5 won't drive my autopilot pitch. Aspen costs too much to drive it. I don't have the budget to replace the autopilot in 2020. ... waiting for a better option I think.