I really enjoyed that video CTF. I think you did a fine job editing your observations after the drive...nice. I've heard that same sound-the clanking brake abs engagement (I think). It's annoying but I noticed when I turned off stability control, it was much less intrusive- not gone however. Did you switch it off? I can get it to replicate on asphalt too if I turn wheel violently enough.
The beach driving is something I lust for.....not allowed here in South Carolina.