Sidenote: For a WAAS install, the boxes are replaced, new wiring is added as well as new antenna's.

As far as looking at a 530/430W vs the non-WAAS, you can't tell a difference at face value, but they will be new ones installed. Few menu items are added, but nothing crazy.

If you can have Roll Steering(GPSS) to your AP, that's highly recommended also if it hasn't been done before. It's very practical with the WAAS features