Thank you for the info provided. Update, as I have removed the ADF to make room for a GPS (still thinking the 175), but trying to decide what indicator best fits my needs & budget. I've also heard "internet rumors" that something new from Garmin might be released at OshKosh this summer so waiting to see what transpires. Current indicator options (in order of ascending price) are to either install a used GI-106A, new GI-106B, or a G5 DG/HSI. I'd really like the G5 HSI but have been informed by an avionics installer that it costs nearly $6k installed, which would likely drive the GPS install price above $12k ($6.5k for GPS175 and $6k for G5 HSI)....also knowing if I get that far into a panel upgrade that I'd likely convince myself to remove vacuum system and add a 2nd G5, so more $$$. With it being a C150, I find it somewhat difficult to weigh the options, knowing what add pilot usefulness while also considering impacts on future value. Possibly for now due to budget, maybe best to just pickup a GI-106A and next year tackle a dual G5/Vacuum removal. Thoughts appreciated.