The base makes for a nice easy mount with the pool pump and allows the use of the included split 90's to connect a supported Hayward pump directly to the input port on the filter, without it you will have to engineer your own plumbing from the pump output to the filter input. This is not necessarily a bad thing as this this can allow you to add a diverter valve if you need one for draining your pool, etc. without the water going through the filter. I have a base on my EC75, but only because it was bought as a kit which included the filter, the pump and the base, all it really does is allow for a slightly more compact installation on the pad and elevates the pump up off the ground a bit. One word of advice when you go to install your perflex series filter add screw together unions or the supplied? screw apart valve on the output fitting so you can at least remove the top if you ever have to service the flex tubes. I also highly suggest adding an optional backwash valve in place of the backwash plug that comes with the filter, any cheap PVC ball valve will do, but I suggest getting a threaded one and use threaded adapter and a union fitting here too as after a couple of years the DE compound will tend to make the valve stiff to turn, and you may want to replace it.
Ike.