This is what I used. $30 and covers the whole car. Just be sure to wash and thorough clay bar it first. It's easy to apply, just time intensive. Totally worth it, though - my 2008 IS looks like it's ready for an auto show every day.
It’s a problem with the whole industry, just so much nonsense, intentionally deceiving marketing. I pulled this from the fourth hit for “ceramic coating” on Amazon, one of the to selling ceramic coatings:
> Super Hydrophobic Anti-Scratch 9H Diamond Hardness.
That 100% implies that they’re going off of the moh’s scale and not the pencil scale.
The auto detailing industry reminds me so much of the stupid fucking psuedo-science essential oil industry it’s crazy.