Mileage, condition, modifications, number of owners, clean Carfax/title? All of those matter a lot more than the color.
In general, a '15 if it's been used more than 20k miles, is going to be worth somewhere in the high 40s to low 50k range, more than likely. If it's been modified, you can expect 10-15% less. An unmodified low miles Sublime M6 (less than 3,000mi)... different story. Close to 80k for one of those at auction wouldn't be out of the realm of possibility.
The asking price will also depend on how fast you want to sell it or how much you have to have out of it. You can TRY to sell a modified car with 25,000mi on it for $70,000, but you might have to spend $2,000 in advertising over the course of a year to do it. But, if you wanted to sell it quick, you put a $52k OBO on it and will likely get offers in the 47-49k range in a week.
To get your price, you have to find the buyer for the car. Take me for example. I would be game for a '15 Sublime M6 if it had less than 10k miles on it AND ONLY if it was unmodified. I don't buy modified Hellcats. I don't care if it was tuned by the best tuner on the planet... I simply will not touch a Hellcat with a P1400 code unless it's for sale on a police auction with a starting bid of $20,000. The further a car is from stock, the smaller the pool of buyers. The more miles, the smaller it gets again. Thus, if it's modified and well used, the moving price is going to end up low unless you plan on sitting on it for a while until that golden unicorn buyer shows up for the car.