FOR THE PUMPS:
If they are not upgraded, you have the 'sprinkler value' system (Orbit Brand System Valves) or the ?hippo ballast system?. One aerator pump fills the bags and a different Rule Pump will drain the bags (each bag has a Rule Pump). They will work, but you will soon have issues. They were a pain in the azz. No Vent Lines. No Check Valves. Slow b/c all bags will share that one aerator pump to fill and one thrul hull fitting.

One of the best upgrades on my boat was to get rid of all that.

Most people are upgrading to the Johnson/Jabsco reversible pumps. That is what's on the new boats starting from 2009+ Usually 3 pumps on the boats. Now they are going with >3 pumps on the 2018 models. To swap out to those pumps will start at 1k-1.5K for parts. No labor.

There is another thread around here or on the Moomba Forum that describes how the upgrade the pumps w/o the investment in the Reversible Pumps. It deals with installing 3/4 motorized ball valves. There are other threads that talk about using >1 aerator pump, but you need to drill an add'l 2 thru hull fittings in the bottom of the boat to increase flow.

Aerator:
Less AMP draw
Lower Cost - but probably not by much in the end if you replumb all the bags - depends on how many pumps you install.
Air Locks/Do not empty all the way

Reversible:
More AMPs draw. Run the pumps with the motor running.
When it's done (with vents) your bags will look like raisins. Completely empty.
Easier Install
More Expensive - but not by a big amount

If you compare the bigger Aerator vs Reversible pumps, there is probably NOT much difference in fill times with the same 1" or 1.25 lines and thru-hull fittings. Aerators might me faster, but I know the Wakemakers came out with larger Ballast King pumps. But there IS A BIG difference in the standard pump setup.