As far as I know, there is no such thing as a TAWS enablement for the Area 660. It does Terrain warning, but no such thing as callouts 500ft above runway, altitude loss after takeoff, etc.
Normal terrain warning is an out of the box feature for the GTNs as well – only if you need those callouts or are required to have certified TAWS you need to invest in those enablement cards.
500ft above
It does…
It actually gives you the main thing for IFR: CFIT protection.
Obviously I am saying this partly tongue in cheek but it is a good exercise to find out what exactly the certified systems give you. And you are going to have a hard time finding out… I have tried this with Garmin, Honeywell, and probably others, years ago. The info is confidential. It appears that you get some accounting for aircraft performance (whereas the handhelds like the Garmin Aera 660 and the Garmin 496 just project the current 3D trajectory for 2 minutes, AFAIK) and some more precise allowance for flying a published approach. And even on the 496 I was completely unsuccessful with Garmin; they refuse to talk about it.
So these companies charge 3 or 4 digits for some software + data but they don’t document what it actually does.
Well TAWS-A and -B are standards so there are certain things they must do. Some of the algorithms used are however somewhat vague.
Or you can just activate TAWS B (eTAWS) on your Lynx NGT-9000 transponder.
Or just the TerrainVision option, which is about $800.
Lots of extra functionalities on this tiny unit, ADS-B in and out, wheather, active traffic, terrain awareness, aural warnings. Makes no sense to go the Garmin route…