Looking at the NADA site, high retail for your car (with 100k miles, you didn't say how many you have) is about $10,000 and low retail is about $7800. Wholesale will be about $5500 (that's your trade-in value). A dealer that is buying it outright would probably pay about $4500 cash. This is for a stock car that they could sell to anybody. A highly modified car like yours has zero value to most dealers. Only somebody like Kompact Kar Korner or Detroit Autoworks would be willing to touch something like that and they're not known for their generosity to either seller or buyer. I've worked in the business for a long time and, unfortunately, that's the way it works. Your car is only worth what they can sell it quickly for, not the time, effort and money that you put into it. To make the situation worse, most consumers see a supercharger and immediately think its been abused, which is usually true.
Good luck.
