No, you do not need tdo update to a different ROM. I have it installed on my Tilt, and have not changed ROMS.
I first went with the HTC Cube, but have changed to the
SCPLF Cube, as it has 4 sides.
If you want to get rid of the bloatware, etc, I'd suggest you do that before installing a bunch of other stuff. actually, I don't know for sure, as I haven't done that. But I'm a bit scared to go do all that now, as getting everythign set up again,and resynching, I'm afraid I'lll double all my calendar appointments.
I'd also suggest having backup software and doing backups before you start. That way, if somethign screws up, it's easy to get back to where you were in the first place.