[Trippynet]

I think upgrading the CPU and graphics is fine without a reinstall as both are from the same family (MGRAS for the graphics, both R10k for the CPUs). Now going from Extreme to IMPACT might involve a bit more work, but to my knowledge you can just upgrade different versions of IMPACT via a simple swap. Of course, I stand to be corrected here?

Cloning the OS wise, use the xfsdump method from jirka's link. I use this process (automated via a script - there's one at the bottom of Ian's site that does most of it) to duplicate drives regularly for backup purposes. I have 3 clones of various ages of the system drive in my Indigo2 and Fuel that I refresh periodically. Going larger or smaller via this method works fine.