nobody wrote:
I guess I've been living under a rock. I wanted to update the VFR GPS in
the panel to an IFR model. I started getting quotes on recon GNC 300XLs.
The units themselves were about 2,500-3,000. I was shocked to find out that
I had to install an annunciator, a new indicator and approx 30 hrs labor
bringing the total cost to around 8,000. I checked several shops and got
the same story. Is it typical to spend 25% of the value of the aircraft on
just the IFR GPS? If I installed a 530, the receiver and install would
probably cost close to 80% of the value of the aircraft.

Your absolute expense dollars sound about right. The percentage of the value of
the aircraft will, of course, depend on the value of the aircraft.

IMO, and as other have also pointed out here, the additional capability over and
above a non-certified moving map is not that great, either, unless you
frequently fly to a runway that's served only by a GPS approach. Most of the
benefit of certified GPS can be had without the certification.