That link is just the corepack, you need the 'complete' unit with control head. That what you are looking at is the course computer, compass, and steering gear. Figure on about 500 for the control head. Anytime you see that unit at about 1100 bucks, it doesn't include the control. You can figure spending about 1500 bucks or a little more. Wait for a sale, I did.
I hesitate to advise this, because it makes little difference WHERE you buy it, but you may want to consider going with Defender on this one. I wanted to buy it from this site, but was told it would not be available for awhile. But Raymarine has earned a stellar reputation for sorry customer support, and a reputable company like Defender, Hamilton, etc. could give you some back-up if things go wrong. I know for a fact Defender will.