Don't need the EZ boom. Did it with my Hardi. I have the EZguide500 and the Hardi 5500 controler no other in cab boxes needed, just some cables. You will need a Jobcom box on the sprayer though if you don't already. some do some don't, I had to put one on.

Here is a link that explains how to doi it- http://www.hardi.com.au/en-au/TechnicalInfo/~/media/extranet/australia/Website/Support/manuals%20operators/controllers/Trimble-HC5500-Installation_0909.ashx

Swartzrock Impl. Charles City IA. helped me with mine. But the link is full of info.
Works very well.
Good luck.