Experience with heated-seat retrofits?

It seems my gf is car-shopping. Because I'm so obviously happy with my car, she is including Prii in the cars she's considering (the c or the v anyway), though she is also considering some conventionally-powered Subarus or Hyundais.

Heated seats are a selling point for her. I had never given them much thought before, but they seem to be pretty common now. The carbon-fiber fabric elements that go under the upholstery fabric seem to be pretty inexpensive and widely available (e.g. Amazon), so it's no wonder that manufacturers are throwing them in as a customer-pleasing feature that costs the mfr next to nothing. Apparently Hyundai is including them in some base models. It's unfortunate and seems kind of shortsighted that Toyota is still trying to use them as upsell bait to the highest trim lines. Plus Toyota only offers them packaged with the Softex seat covers, which she doesn't even like.

This seems like a case where it would make a lot of sense to just get the lower trim line with the upholstery fabric she actually likes, and then add the heat elements. Unlike me she tends to buy new, so she might be more reluctant about modding the car right away, but it doesn't look very difficult. I could maybe invite her to help install a set on my Gen 1 as proof-of-concept and to see how it goes.

I do see one posting by an old priuschatter and a pretty good installation video and another one. The dude in the second video, not content just to customize the car, goes on to customize the customization ... in a later part of the video he mods the controls that came with the heat kit to make the switch light up with the dash lights! ... and throws in a further comment at the end about intending to change the switch light color.

Has anybody else had experience installing these, and have any preferred (or unpreferred) brands or suppliers, or any other tips?

Thanks,
-Chap