What will you be doing with it? Motoring in flat water the 4000 will be fine, and save $$. If you get into open water the 6001 (with appropriate ram etc.) is more the answer. We have the 6001 on an 18,000# boat and have been very impressed. We were concerned over potential energy consumption with the 6001 but found that by adjusting the deadband when in rough water and making sure the
rig is well balanced it has been quite low.