It is not a difficult mod, but due to the nature of it, one has to fiddle quite a bit to get the thin audio channel wires coming from the tone arm connected well. If you happen to only have audio on one channel, make sure to check those wires and connections first.
This kit seems to be an updated version since the mounting holes on my tone arm allow for cartridge alignment which is a plus.
Also, I could not mount all of the parts exactly like described and had to be a bit inventive, but that maybe down to a revision of the Numark itself.
Overall I am pleased. Time will tell if this mod holds up well, but I am confident it will.