I have done this upgrade several times and you are going to need a lot more than just the hydraulic unit to complete this project. Additionally you will also need a T&T relay box, a switch at the helm to operate it, and cabling between. Various options are available for the switch.
You do not need to completely remove the motor to install the hydraulic unit, but only need to tilt motor up and engage tilt up latch, remove screws and top attaching pin from tilt assist unit, remove mounting screws for port transom bracket, and remove nut from port side of tilt/steering tube. This should allow you slide the port transom mounting bracket sideways enough to slide out the tilt assist assembly and slide in and install the T&T hydraulic unit. Warning: should also brace the motor up with a 2x4 as well before starting the change over. Also can use tilt ram top attaching pin and plastic bushings from the tilt assist unit being removed if not provided with T&T unit you purchase. Will also use the same mounting bolts as well.
T&T motor may have 2 or 3 wires. The 2 wire motors are the later design, but both will work. How the motor is wired depends on which you have. I can provide diagrams for the wiring if needed, but can find a lot of information and diagrams by searching the Johnson/Evinrude Outboard forum. Hint: Motor will have both green and blue wires (blue wire is up and the green wire is down).
This is not a project for those lacking in mechanical & low voltage electrical aptitude, but a very worthwhile upgrade in the end. My .02 anyway.