A 2 valve kit is around $600. Be sure to ask for the detent option for 1 valve. Installation is pretty easy. The instructions are laid out in good step by step order. Takes a couple hours or so.
Each valve kit is about $300 so getting the 2 valve kit (both valves in one kit) saves $100. Always nice to have that second set of remotes, especially if the one set has detent for the Backhoe.