Robert M. Gary wrote:
Since the bulk of the cost is installation the actual GPS unit you
select will not have a dramatic effect on end price. A GNS430 is about
$11,000 installed here. Any other GPS is + or - $1000 or so.

Not necessarily. The GX55 I had in my 182 and now in the Bonanza costs
nothing to install if you replaced a loran in the process and the loran
antenna was on top of the fuselage. The expense will be in getting it
legal for IFR. An terminal/enroute only box costs far less to get legal
than an approach box.