Garmin are the bastards that refused to repair a non-WAAS 430 unless it was upgraded to WAAS. If we didn't upgrade the only other alternative was to buy a used unit that might fail anytime and without a warranty.
End result: The owner had little choice but to upgrade it to WAAS as well as the 530 unit so the two would continue to talk to each other, including replacing the aerials to WAAS compatible equipment.
The real bastard is that we don't even need WAAS capability in that aircraft.
Most peeved with Garmin, I am.