Mark Hansen wrote:

Will the 530 allow you to fly a non-GPS overlay VOR/Loc approach
using the GPS? The 430 doesn't. [...]

That's only for GPS-based navigation. Flip the 430 or 530's CDI
switch to VLOC, tune in the NAV portion, and enjoy the approach.

That's what I mean by "Using the GPS". When you switch to VLOC,
you're using the VOR/Localizer, not the GPS.

Then I don't see why you're splitting this hair. An integrated
GPS/nav box like the 430 will let one do the approach either using
official VOR/LOC data, or with unofficial "situational awareness" GPS
data. It is silly to denigrate these units with "doesn't ... allow",
when they are strictly more capable than a GPS-only navigator.

- FChE