Hi Anro, that's hard to say as it was part of a much bigger avionics upgrade that encompassed the ADF, audio selector, most of the cabling plus a few other bits and pieces.
I think labour-wise the GNS was projected to take about 35 hours, a lot of that work is in making up the cable booms, and there's a fair few hours of testing in it as well, as it ties together so many functions in one box. Add materials etc., and I'd say budget at least 4 grand to put one in (assuming hourly rates of around 100 bucks).
If you tell me what you're starting out with, and what you want to do with the machine, I might be able to give you an idea what you might be looking at, but I'd definitely recommend talking to a few avionics shops and other aircraft owners for guidance.
I learned the hard and expensive way that it only makes sense to go so far with fixing old avionics, as some of this stuff is so old that it will keep breaking or simply going out of tolerance (same result, a big bill), so in a lot of cases it does make sense if you're changing stuff anyway, to replace some extra bits and that way keep future bills lower. Having said that, I kept an old King KX175B as my second NAV/COM and it has served me well so far. The KR-85 ADF I had overhauled for a lot of money had to come out, though, but ironically because it wouldn't fit into the upgraded panel layout.. so
FTDK if you're still looking for those ADF spares, I might have something for you
As for the 530 itself, I'm extremely happy with it, it works very well in VFR and IFR, and is probably one of the best compromises between TSO'd functionality and price.
