Upgrading HDVR2 from 3.1.1e to 6.2

I am in the process of changing out a failed drive on my Hughes HDVR2 and would like to install a clean 6.2 image so I can hack the extra features using the Zipper scripts. pTV recommends sticking with the existing operating system (my Tivo is currently configured with dual drives running 3.1.1e). Are there any known issues going to the 6.2 OS on a box that is running 3.1.1e? Has anyone successfully pulled it off? My plan is to revert back to a single drive config ~ 250GB and follow Gunnyman's instructions to make the swap. Any experiences out there to share? Trying to avoid a problem.........