Shifters - Air Filters Oct 15, 2009 6:57:58 GMT -8 Quote Select PostDeselect PostLink to PostBack to Top Post by billcox on Oct 15, 2009 6:57:58 GMT -8 The Board decided at the meeting October 14th to allow air filters for the Shifter classes. The 14" silencer with the turn-down tip is still required.