I have added them to my current and last boat. First one was a Sideshift, 2nd was a lewmar. I feel the "tunnel" gives it a bit more thrust than the "open" design of the Sideshift.
Cost is really going to come down to a couple BIG pieces.
1. self-install or shop
-if shop, count on about 2x min the cost of self.
2. current setup on boat.
-Do you currently have batteries easily accessible for use of the thruster?
-Do you want to keep the systems separate from other ships' systems?
-Distance of runs to make everything happen
I have a dual station boat, but I NEVER use the thrusters from lower helm. I drive from upper 95% of the time and 100% of the time for docking. So the need for dual station setup wasn't needed when I added the setup.
I assume the boat already has a bow thruster, so will you want to integrate with that one or have sep. stand-alone controls? I have a older Wesmar in the bow and it's a beast! the boat JUMPS when I kicked that one on...
I wanted a single set of joysticks, single power on/off and control in one place. Had to get a bit creative with some relays, but has worked flawlessly for ~3 years now...
My suggestion for you would be:
1. get a 24v option if you can, tons more power!
2. if you are even close to the 75% max range for the thruster, get the next size up!!! Nobody ever regretted having too much thruster! As someone else mentioned, they were on a boat that had one that was basically useless in any sort of wind...
So there isn't really a short answer without knowing more of what you have and what you want...
Pic attached shows the cost of the "kit". But you also need to figure cost of wire, batteries, misc. "stuff", possibly secondary charging source, etc, etc...