I helped my hangar neighbor upgrade his RV-7 recently. Not a simple job but not difficult either. Primary reason for upgrade was to have auto-trim tied to the AP. We're also going to replace his old stick grips with Infinity grips for additional buttons/functionality.
Assuming RV-6 as in your profile:
You'll need the roll trim kit from Vans for your plane and a
trim relay.
Drilling the mount holes required a 90? drill and associated drill bit sizes (#28 for #6 mount screws) and step drill for snap bushing installation for wires to pass through the side of the center section seat support. If the pitch rod needs to be disconnected for access (likely) you want a
special tool for reinstalling the shim washers on each side of the rod end.