Eclipse, I assume you can't afford it anymore, or no longer need a car?
In any case, if you're NOT trading it, I'd recommend selling it privately. Especially if a desirable colour with sporty options and look. And depending what area of the country you're in too - are sporty cars valued where you live?
When trading, you'd save money by only paying taxes on the difference between the value of the new car and the traded car. But, they'll give you wholesale cost for the car because they then will put it on the lot or sell elsewhere for market value to make a few hundred or thousand. If you're not buying a new car, might as well try and sell it privately.
Not everyone's aware of Mitsu's financial crisis. Some people really love the Eclipse and would pay handsomely for the look.
Regardless of Mitsu's financial status, public perception and generally their cars are ranked behind Toyota, Honda, Subaru, and perhaps Nissan and Mazda. Depends on the model, but overall. Therefore, resale values will reflect this. They are also a relatively new retailer in Canada, so the dealer body is weaker and people here don't know much about them or have any great experience with them, so this affects residuals negatively as well.