Couple things to keep in mind when determining a selling price for a car.
Modifications, cosmetic or otherwise, do NOT increase the value of the car. In fact, if anything, they usually DECREASE the value, because now you have taken the generic, mass produced product that everyone is familiar with, and tailored it to your personal taste. Unless you find someone who likes basically the same exact modifications that you've done to the car, it will usually HURT the value.
Repairs never count towards the value of a car. Unlike a house, a car is NOT an investment, meaning any money spent on keeping the car operating properly is just money down the drain from a financial standpoint.
And the rear struts mounts rusting that badly.....I'm sure you know that's extremely not good. Given all this, I'd say if you can get $2,600 for it, I'd take it in a heartbeat and be done with it.
