The Total COntrol system typically comes as a compete system with Automation in mind. Using ORP and pH sensors, it is able to activate the cell and an acid pump whenever those levels sway from your desired set points.
You can also get this system a step down, without the automation. That is, without ORP and pH sensor and the Pool Chemistry Controller (#75001). However, the Digital control box for the Total Control family (#75003) is different from the normal Digital controler (#DIG-220) and are not interchangable.
You can maintain pH balance without the acid tank (#75005). I just know from experience that most homeowners have quite a time with water chemistry balance problems due to increasing Calcium hardness and pH, which result in scale formation. YES, you can keep the cell scale free without the acid tank/pump as long as you maintain your water balance.
Should you go the AutoPilot route, I suggest going with:
75003 - Digital control unit for use with Total Control
94107 or 94113, manifold assembly with SC-48 or SC-60 cell, respectively. Which cell to go with? Whichever you can afford, with the thought that the larger cell will last longer.
THEN, should you desire to upgrade to the acid tank/pump system, you can alway add on at a later time.
To be fair, I should note that Hayward also offers the ORP/pH automation with their system too.