Sam Imbadi, great question and thanks for asking! I applaud your goal of taking control of your chemical application. Doing so helps with cost control, effectiveness of application and shows respect for our environment! The basics of true rate control require flow monitoring and control, pressure sensing and the ability to adjust it as well as some form of speed input to be able to adjust the rate. The goal is that you maintain a target rate as speed varies in a given range of speed. So there are several things that need to be added to your system to be able to do rate control. A GS2/2600 John Deere display is only a display. It has to have another box/rate controller to run and monitor the system. A GS2 display is also truly an aging piece of hardware and is no longer available new. If you have one you can get a re-manufactured unit through a John Deere dealer. There may be better options for you depending on what your goal is. My advise to avoid throwing good money away is to get your local expert involved. They need to see the sprayer, discuss your application goals and truly evaluate the situation in order to get you where you want to go. Just because things plug into each other don't mean they work together. There are also a lot of things that the operator needs to understand so that they can effectively run the machine within the control range of the machine. I would suggest getting your local John Deere dealer involved to get your best results.