If you are going to fly IFR in France, I would advise that the panel should be equipped to do LPV. More and more airfields are getting rid of their VORs and NDBs and very few or no new ILS approaches are planned.
At the same time LPV approaches are being introduced at a rapid rate.
If, however, you are happy planning to do all your flying to an airfield with an ILS or to never want to do an approach to a DH as low as 200ft. Or you don’t plan to have a coupled autopilot, ignore the above.
(Warning — long post)
The good news is that your panel is already quite well-prepared for what you want to do with the GNC255A and the G5 installed. If you are looking for a no-frills solution, the only thing you need to add is an approach-capable GPS. I would not install anything not capable of LPV approaches today.
Regarding the support of the GNS 430(W) series, Garmin just announced that they will/can no longer replace the displays of the GNS 430(W), and will charge you a punitive assessment fee of $500 if you decide to send a unit in and they determine the display is faulty. They will keep on repairing other things for their flat fee of ~$2000, and the 530(W) is not yet affected. And just for correctness, the only version of the 430 that is completely unsupported is the early 28V-only non-W version. There never was a 14V-only version and all 530s are 14V/28V as far as I know.
So, in my eyes, the decision tree can first be split into two main branches, “supported” and “on the edge of being unsupported”.
The “supported” branch further contains the “new” and “used” branches. The “new” branch only contains the GPS175 within your budget. It does offer all capability that you need and in combination with what you already have in the panel a fully IFR-equipped panel.
As mentioned, also replacing the KX165 with a GNC355 or the GTX330 with a GNX375 gives you some extra capability, but I don’t think you will recoup enough to lower the device price to your budget.
Also be aware that these devices lack some GPS functionality, eg. they don’t do VNAV should you decide to install a GFC500 autopilot.
The “used but supported” branch does not really contain anything but a used GTN650. They sell around €8000, so €2000 over your budget, and there are practically none on the market. But it’s a supported, modern device and gives you added capability, an 8.33 COM and a 2nd NAV receiver (which I don’t really feel necessary personally). If you are able to up your budget to that and find one, it would be the best solution IMHO.
The “on the verge of being unsupported” branch contains the 430W and the 530W, currently selling for around €4000 and €6000, respectively. These prices might change in light of the recent support limitations. Here you have to decide how adventurous you feel — if it dies, it might mean hunting down another serviceable device.
Personally I’m not too worried about the 430W situation, there are gazillions of these installed and I guess there will be a way to keep them serviceable. But as mentioned, that’s a question of your own risk appetite.
That being said, in terms of capability, installing a used 430W or 530W would be your best option strictly within your budget, since it also allows you to replace the KX165 by an 8.33 capable COM and it keeps the second NAV receiver. A used 530W might be worth a thought since it is not yet affected by the end of display repairs. Of course, that could be announced tomorrow.
TL;DR: If you manage to up your budget and find a used GTN650, get it. If you want to buy new/supported within your budget, get a GPS175. If you feel adventurous and are open to finding creative solutions for problems, get a used GNS430W.
mri wrote:
As mentioned, also replacing the KX165 with a GNC355 or the GTX330 with a GNX375 gives you some extra capability, but I don’t think you will recoup enough to lower the device price to your budget
I appreciate all the feedback. One thing the shop told me today that I didn’t think of is that the GNC355 has com but not nav so I will be down to one (GNC255A) for nav. The suggestion was to go with the 175 and leave the KX165 since it has GL like the KX165A. Only other solution was to go with the GNS430W that has com/nav radio but as many pointed out, probably not the best way to go.
My 6,000 budget was just hardware, not the install etc. I will look at the GTN650 but I think it is a bit big and will require more modification.
I would not worry about that. Separate GPS and NAV receivers are good redundancy in my eyes. At least around here every place that has an ILS has a GPS approach, so if the GNC255 dies you can complete the flight with the GNC355. If the GNC355 dies, you can still fly an ILS with the GNC255.
mri wrote:
Separate GPS and NAV receivers are good redundancy in my eyes
Yes but I was referring to the fact that the GNC355 only has com, if the GNC255A died I will only have com no nav.
If you want to buy new/supported within your budget, get a GPS175.
Sounds like the best option to me.
Another one re: Garmin GNS 430/530 – https://www.avweb.com/aviation-news/garmins-gns-430-530-sunset-takes-another-step/
“Garmin’s GNS 430/530 Sunset Takes Another Step”:
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The long-expected discontinuation of maintenance support for Garmin’s iconic GNS 430/530 series navigators has taken a big step. The company has posted a service advisory telling customers that “*display repairs for the WAAS and Non-WAAS GPS 400, GNC 420, and GNS 430 are no longer available* and have been discontinued.”
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But be forewarned, if Garmin must return a unit as “unrepairable due to the announced unavailability of repair parts,” there will be a $500 processing fee, per unit.
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But be forewarned, if Garmin must return a unit as “unrepairable due to the announced unavailability of repair parts,” there will be a $500 processing fee, per unit.
I think the people who run Garmin are immoral, as well as short sighted in business (the two are so often correlated 
) Somebody is going to outcompete them someday, it’s just too rich a target.
Silvaire wrote:
I think the people who run Garmin are immoral, as well as short sighted in business (the two are so often correlated ) Somebody is going to outcompete them someday, it’s just too rich a target.
I am a capitalist. Avionics shops can repair these units as Garmin publishes the maintenance manual. If some one is dumb enough to send a GNS430 back to be repaired with a dark or damaged screen after having been forewarned that it can’t be repaired, the $500 fee is reasonable IMHO. If you want an example of unreasonable, try sending a WX-500 in for repair to Extant. The flat rate repair is $6400 and the fee is charged in advance regardless if the unit is repairable. No one else is authorized by FAA to do any repairs on these units as a maintenance manual is not available.
Avionics shops can repair these units
Can they? My understanding is that the problem lies with the availability (or rather lack) of the screens as replacement parts.
