The complete kit is around $20,000 but the autopilot component was already an upgrade that the dealer had selected when they ordered the boat. From memory adding the joystick and all the features like fishpoint cost me around $7,000 extra.
With regard to adding extra hours, the way the weather is this year I’ll be lucky to add two hours! Anyway, the dealer said with modern motors they can quickly bring up a report which shows engine hours by revs per minute. So you can quickly see how many hours the boat has done actually travelling and how many at idle, etc. He said, in future, buyers of used boats will look at the two figures separately (idle/low revs versus cruising/open throttle range).