You have an 8 year old luxury car that isn’t a Lexus. You’re lucky it’s worth as much as it is. 
That said, you should absolutely ask more than book value for it so that people can be talked down to book instead of you being talked down to below book. But like @Mustangman said, you don’t want to set the price too high because then people will decide you’re out of your mind and not bother calling at all.
Were I in your shoes I’d do a very thorough evaluation of the car – as an example, it’s exceedingly rare for a car with 20,000 miles on it to be in “showroom” condition. Unless you’ve hired the detailers that work Pebble Beach, there’s very probably a paint chip somewhere, or stretchmarks in the leather, or something else that drops it below that level. You need to be brutally honest here, because if you gloss over imperfections because you like the car, the buyer will find them and that will be their opening to tell you it’s not anywhere near showroom condition and you need to drop the price a lot right now or they walk.
Then I’d take the high-side private sale price from Kelly Blue Book, add $500 or so to it, and list it with the intention of being talked down to somewhere in the value range KBB listed.