It wasn’t too bad. Took maybe an hour to complete. You’ll need to do some soldering and you’ll need to rebuild the internal battery assemblies with some kapton tape. Pay particular attention to how the wires are run on the assemblies or you’ll have difficulty making the case fit back on. Honestly the most difficult part was sourcing the batteries with the tabs already welded on. While I’d love having a battery tab spot welder, I just don’t think I would use it enough to justify the space to keep one around.