No offense, but Blue Book is usually "off" so to speak. They are too high on retail prices - and way too high on trade prices.
Now, maybe it's changed since I've been out of the business - but most dealerships work from NADA numbers. Here's a link:
http://www.nadaguides.com/Cars/2008/Honda/Civic-4-Cyl/Sedan-4D-EX/Standard-EquipmentIn all honesty, I used to hit the car auctions quite frequently - and I never saw anyone looking at Blue Book value. NADA, yes, Blackbook, yes. The only people that used Bluebook were people with trade ins wanting to know why we wouldn't give them blue book value. That was easily handled by saying "because we aren't asking blue book retail for the car you want to buy."
Keep in mind, the reporting for nada is based on dealers numbers - the numbers that show up on the contract or bill of sale.
NADA is a much better "guide" - but it is also just a guide. There is no "end all be all" book for car values.