Interesting, that's very different from my experiences with it. I haven't tried the Zaino (gotta be something I can buy in gallons and that's more carnauba-friendly) but I like the Griot's a lot better than Pinnacle and Meg's #62/#00, which I used previously.
As far as harshness, I find Griot's pretty mild, much more so than Pinnacle, for instance. Doesn't strip KSG at all, not even after many, many washes. Doesn't compromise the #16/476S I use on my wife's A8, so I wouldn't worry about it being hard on carnauba LSPs either. I use it in pretty strong dilutions and my carnaubas last for at least several months worth of washes. And IMO that "undiluted, will remove tar" is just ad-copy BS; it didn't work when I tried it.
Some of the differences in our experiences might have to do with water quality...but it just goes to show that people have to try stuff like this out and see what works for them.