As often happens with our beloved birds, the failure of an item in my panel has prompted a reach into the wallet. I have an S-Tec 50 w/alt hold, electric trim, and GPSS. The autopilot will no longer fly the heading bug and the DG is worn out. The GPSS still works great. In lieu of rebuilding the DG, I have scheduled to replace with the new Aspen E5. I went this route in anticipation of an eventual upgrade to the S-Tec 3100. My question is how much of the vacuum system should I remove or keep? My inclination is to keep the Altimeter and VSI for backup. What say you? Also in the mix is a IFD440 swap if the budget allows. Thanks!