In preparation for collecting plane next week with Aspen installed I have been going thru the Sportys video. My plane has 2 Garmin 430s (not WAAS), STEC 55x and now the Aspen PFD. Having watched the training video one thing is causing me a lot of confusion. Will I now have GPSS on both Aspen and STEC and which one do I use. Training instructs you to put STEC in HDG mode for Aspen GPSS to work. This seems weird to me as I have been pressing NAV twice on STEC to get GPSS up till now! The question then arises as to how I fly the autopilot using the heading bug (presumably I disable GPSS on the Aspen and put STEC into HDG mode?) Help!