I doubt that an upgrade is needed. I think the problem is simpler than that.
As a guess, it might be that the pump has ingested a piece of debris and is gagging as it tries to push it through. This isn't as uncommon as you might think, and sometimes involves a piece of plastic that dropped loose when the plumbing was cut into the wall of the tank.
This is easily checked. Disconnect the plumbing and wiring from the pump, and remove the pump to a workbench. Remove the working end - it is held on with a few screws. This will expose the black rubber diaphragm with the flexible pumping chambers molded into it. You can remove the entire diaphragm and look into the chambers while rotating the pump slowly by hand. If you find something, remove it.
If there is a foreign object in there, it may have ruptured the diaphragm, in which case you will have to replace it. Sureflo makes a simple and inexpensive rebuild kit for the working end of its pumps. Commonly available. Based on the model number of your pump, you can get one and install it easily.
The Sureflo web site (and of course YouTube) has pictures and videos to make all this clearer.
Bill
Addition: I don't recognize the sheet metal mounting structure that your pump is sitting on. It is certainly possible that something has come loose within that structure, and is thrashing around as the pump rotates. Add that to your "check it" list.
