Kelley Blue Book is pretty close to price accuracy not unless you have special edition Z or a classic Z. To get the correct value for your Z you are trying to sell go to a professional vehicle appraiser in your area and they should be able to get you a spot on value for your Z. Also if your Z is in like new or excellent condition your Z would probably do well on eBay Motors. I recommend trying to sell your Z on eBay Motors or Autotrader I had very good experiences selling vehicles in those places.
www.kbb.com www.ebaymotors.com www.autotrader.com