430 is $ 300XL, that the case. 50% about?

The installation is much messier since you
need a relay box to switch your indicator
from your VOR to the 300XL GPS. So that could
easily eat up part of the cost saving, both the sw box and the
hours to wire it up. Very tedious. Check quotes carefully.

FAA approval probably slightly easier on 430.

Another equation:

300XL old generation, nasty operation (tho not real bad)
430 sweet operation-- very nice implementation.

The sting on the bucks will be forgotten quickly.
The difference will be you think.

Oh.. the 430 will affect the value of your plane more
positively.

Bill Hale BPPP instructor
430 enthusiast.