The CF Dinan CAI's are no longer in production so most people who sell them can ask for $300+ for them (I got $325 for the one i was selling). Mind you these intakes went for $450+ tax when they were available on the Dinan website.
Goodluck with the sale, try posting it on Bimmerforums.
2012 Mercedes-Benz C250 Coupe-SOLD
1996 BMW 328is- SOLD
1998 Mercedes-Benz E430- SOLD
1990 Ford Probe Turbo- SOLD