Not all filters are the same...The earls filters we used were too small in diameter and length and caused fuel starvation problems, the Aeromotive ones are much larger with a huge amount of surface area. It all depends on supplying flow, our Toyota has fuel pressures at 60psi so we would need way more flow than say a stock Ford or Chev system with much lower pressure requirements. I think we used the 100 micron / 10 micron combo after wasting money the other way, not only on filters but on testing costs, and sending the injectors back to RC twice to get them cleaned when they plugged up after only a few hours of testing...Yes the Aero stuff costs a good bit, but a poor fuel system will cause not only performance problems but can do major engine damage as well.
Be careful of the specs on the earls filters, I remember finding a major error on the flow rates on the Summit web site. I believe all the sintered bronze units flow the same, all the mesh ones flow more but can't filter small enough with a good flow. Double check specs on Earls site directly.
All the prefilter needs to do is to catch the particles the pump can't pass without damaging it, the post filter needs to catch the particles the injectors can't pass...
Call Aeromotive, their technical department is very helpful...Curt