Here will lye your problem. In 3 years, when you are bored stiff with this car, or you get married and start a family in 5 years and need something more family friend, or more friend friendly, or something that is more business friendly and you need to sell it, or trade it in, you're going to be buried. You will never even be close to even with your loan on this vehicle, you will always be upside down.
In with winter of 2000, I decided I wanted a new truck. I leased a 2000 Ford Ranger, 2WD....it was $211/mo with $0 down for a 24 mo lease. It was what I could "afford". By Dec of 2000, I had gotten a new job paying more, but WAY further away from home (20 miles each way), and we got 55" of snow that Dec. By the end of that Month, it didn't matter what it costed me, I was fed up. I traded it in on a New 2001 Ford Ranger with 4WD....it had everything in it for a 2001 Ranger and $439 a month for 36 mo lease! 2 months later, I got over confident in my 20 year old driving abilities and smashed it into a wall on the icy freeway. 15k worth a damage, and they FIXED it. I drove it for 2 more years til the warranty expired....but then I was stuck. I was still 7k upside down in that truck and nobody would roll it into a car loan....no bank would do it, no dealer would do it, and I didn't have a dime in the bank. I had to go the the Bank of Grandma to get help. I borrowed the 7K to pay off the truck lease, and borrowed 14k to buy a Used 2000 Pontiac Grand Prix with 60,000 miles on it! That still made my payment $400+ a month. When I finally paid that car off in 2008, it was the greatest day of my life up to that point...I FINALLY wasn't paying for 3 vehicles wrapped in one! I'm honestly not sure what I would have done without that help.
IMO, I would RUN away from this deal. If you really want a new Dart...then just buy a new Dart....Do not roll negative equity into the deal.