WTB PC III USB for Sportster part number 817 511 EX

Not sure about the part number as you posted it, but a PCIII p/n 817511 is $350.99 form Dennis Kirk. The "EX" type looks like they are for CA. Models.
http://www.denniskirk.com/jsp/tpl/cmn/prodlist.jsp;jsessionid=0MS1O0M1UYWAZLA0WTVSM4VMDK 0NCIV0?store=Main&catId=209&np=&brandId=226