I'd skip the mbr, grub, uuid, problems and do an rsync. Here's the script I use for a hot clone using rsynce_backup_restore.sh. You can read the quick-notes and get the idea..

http://programs.rcrnet.net/

On source machine:
Download script
chmod 755 rsync_backup_local.sh
Edit the top of the script with your values
Run the rsync_backup_local script.sh on the source machine
Shutdown services like mysql and postfix etc.. (Alternatively do a mysql dump)
Run it again (runs really fast this time)

On target machine:
Install a base system with a "alternate cd" on the new machine
At boot, type in "cli" this will choose no software, and finish the installation.
Edit rsync_restore_local to your values
Run the rsync_restore_local script.sh on the new machine
When done reboot the machine. It's that easy..