[Al Skierkiewicz]

The rule refers to the one Norgren regulator to provide the primary working air to the robot. This regulator may be followed with other regulators set to pressures lower than 60 psi if desired provided all other rules are followed. Frequently teams attempt to limit pneumatic activity by providing lower actuating pressure to certain devices. This rule is in place simply to insure that every team uses the same energy to provide motion on their robot, namely 60 psi working pressure at a specific flow rate/volume.

Also in the rules...
[R71]
The only pneumatic system items permitted on 2012 FRC Robots include the items listed below.
D. Solenoid valves that are rated for a maximum working pressure that is less than 125 psi rating mandated above are permitted, however if employed, an additional pressure relief valve must be added to the low pressure side of the main regulator. The additional relief valve must be set to a lower pressure than the maximum pressure rating for the solenoid valve.
G. Pressure regulators with a maximum bypass pressure of no more than 60 psi,

Caveat: Rules are quoted from the 2012 rulebook, 2013 rules may be different.

Answering while Indy posted... Camren, no, that is not a legal primary regulator. Air filters? If you are asking about outlet silencers, many teams use them. If you are asking about intake filters, the compressor has them incorporated in the design.