Can't see it taking any more than a week to 10 days. The controller and wiring can be pre-installed adjacent to existing controller, so if they engineered it correctly the new motor will have the same base mount and shaft coupling. Hooking up motor wiring and programing drive will not be a huge deal. I've seen programming and adjusting VFD on 300 Hp gearless motor done in an afternoon. This a basic system, just changing motor from Direct current to variable frequency Alternating current whcih is less susceptible to power surges and lightning strikes. Also cheaper to run. Cable stretch ishould not be a factor in this case as cable is not replaced or removed.