The ELEGOO Centauri Carbon is a modder's playground - the combination of a great price point making for widespread adoption and the quick wins that can be had with simple modifications made it attractive enough for me to buy two and start my print farm with them.
For me though, the insulation was less about improving the ability to print ABS, and more about making them more energy efficient. I really want to minimise the heat being dumped into my little apartment workshop on summer days, and I don't care for PLA at all.
I needed to get the radiator foil fast to get it in time to release the video, so I ordered it off bol.com here for €20. If you're not in the Netherlands or want it cheaper, this roll off AliExpress looks like exactly the same thing, for just €10.
Once I split that cost between the two printers, €10 for this mod is very reasonable, and I got some great gains. I used a small amount of ABS and TPU filament, along with the double sided transfer tape, so maybe add in an extra couple euros in material and electricity. While I didn't measure the energy savings in any way, the temperature and noise decrease in the room alone is well worth the money.
I can't take credit for any of the printed parts in the modifications; you'll find the original authors in this Printables collection. Elvin's Essential Centauri Carbon Mods Collection by elvinhome | Printables.com
You'll also see a few items in the collection that are for the future video... Spoilers.