OK two important facts of life, number one dealers are in business to make money, they want/need to make at least $2000 to keep the lights on, heat/cool the building, pay the office staff, property taxes, insurance, etc, and put food on the table.
Second fact of life, and I KNOW I am going to get a lot of flack for this statement, accessories and personalization of bikes, cars, trucks, etc. do little or nothing to increase the resale value.
So, I am thinking the dealer is sort of justified with his quote, the best way to get what you think the bike is worth is to sell it outright. Now, I'm not sure how it works in your state, but in New York, there is no tax on the amount of your trade in against the total value of your purchase, so say in the case of a new car, if they give you 8K for your car and the one you are buying is 30K, you end up paying sales tax on 22K, which with an 8 3/4% sales tax can save you quite a bit of money not to mention the aggravation of trying to sell it yourself (time is money) plus if something goes wrong with the vehicle immediately after selling it,it comes back on you...