Paul, I followed your guide, followed the link to r3 superboot and got the following results:
first SU flash attempt -- didnt do anything, said downloading boot, booting, and nothing was different. No root
SECOND flash attempt - said downloading boot, booting, but this time, the HTC boot screen gave me some warning about development mode, and when I was done booting, I had root.
I also now have "tampered" in my bootloader. Did I miss something here? I've got root, but I'm curious about the tampered AND the message about dev mode.