May I suggest spoken TAWS alerts are considered?   A subset of warnings given by Ground Proximity Warning Systems.

I don't know how much work this would be. I guess they are audio "clips".

This is a subset I don't think needs aircraft system interfaces:

"Terrain" - When "red" terrain is ahead (time user setting)
"Terrain, Pull up" - When the terrain warning is ignored
"Sink rate" -  Excessive descent rate (user setting)
"Sink rate, pull up" - When "Sink rate " is ignored
"Don't sink" -  Altitude loss during  take off climb out

Not a GPWS term but useful:
"Fife hundred" information message when approaching a destination runway.

I use SD for VFR flying and would not want to feel like being in an airline cockpit. I would simply turn off these warnings.

-- Chris.

Good for you. No doubt you turn the terrain off too cuz you can see that

SteveN, excellent idea. For those who don't want it, it can always be disabled as an option. However, there is nothing SD can't do that an expensive GPWS avionics unit could do a few years ago. 

Absolutely.

I think this is an excellent idea. I use a Garmin Aera for similar support to a GTN 650
There is no measureable difference between the TAWS guidance on the two, but the price difference is immense due to the mad costs of certified IFR kit.