Good luck with sale. If you do find the dyno graph post it up so others can see what the tune is like since thats a very essential part of a turbocharged car. 18k is way up there...I would put the value of your car around half of that depending on how clean the paint/interior/engine bay are. Just my .02, if you really want to make that much back you might consider parting out the nonessentials so you can lower the cost of the car. You should look into putting the interior back to all OEM parts, selling engine # 2, ditching some of the extra suspension goodies, and maybe even getting some cheaper rims.