I'm thinking of selling my car for 07' MCS. The car is in very good condition w/ 25K miles. It has premium/ sport packages, leather seats, H/K sound system, car alarm.
Mod including Tein S-Tech springs.
I'm asking $20K with S-Lite wheels.

 

Nice car, no doubt. Went through the same process with my MCSc, 15K miles, all factory packages, and offered less than what you are listing. Unfortunately, most people want a car for nothing, no matter what you think it is worth. Look at KBB and come up with a price. Best you are going to get at dealership is black book (wholesale). NAM is a great place to get advice, but some people on this site do nothing buy give you a hard time.

Good luck with your sale!