your can just get one from ebay
it does the same thing that the expensive one do for less
but if your like me and like name brand stuff get the aem cold air intake or the v2
check them out here
http://www.tirerack.com/accessories/AccResults.jsp?autoMake=Honda&autoModel=CRX+Si&autoYear=1991&searchType=intake&autoModClar=&category=a_Intake