I have decided to upgrade to 3.5.1 from 3.0.1 on NW65 before doing any
further enhancements on my idm solution. Part of my upgrade documentation is
a rollback plan should things turn pear-shaped.

My upgrade plan is basically this:

apply sp7 to servers (I already have a couple of sp7 servers in the tree)
apply post update to NMAS (3.2.0.1)
* The above steps to be completed a week or so before the next ones.
upgrade the idm engine
upgrade the drivers one at a time testing as I go (Delimited text,
Groupwise, edir, AD, UserApp)
upgrade the remote loader for AD driver (I assume the old RL won't work with
the newer driver)
upgrade the userApp (I assume the old UA won't work with the newer driver)

My rollback plan at the moment (and without much thought) is to image the
two idm servers, and export the driver sets.

Is that sufficient and what would the steps be to rollback the driversets?
Could I simply put back the SYSTEM folders on the NW servers, delete the
driversets and import them again from the export?

What else would/should I need to consider? Of course I'll fully test this
roll-back before moving ahead but I hope not to need it. I have a 3 hour
maintenance window, once a week to accomplish this.

as always, thanks for all and any help.