I just found this because I'm having the same problem with my RB20.
http://weapon-r.com/english/in...=5876 It looks promising. If anyone has used this and it works please speak up!
PS - leesredgt, did you get the "large" Airinx filter or the "small" one? I'm trying to figure out how big either one is because I'm having hood-clearance issues with my intake.