Keep your Dart. I went thru the same thing when I was younger, getting tempted by this or that deal. I know it's hard, but be content with what you have. If you really want another project, save up for it, don't trade your Dart.
What this kid is contemplating reminds me of the huge mistake I made in my youth. I took a 78 Blazer instead of buying a Dodge Challenger because all my buddies were off roading and I though it was cool. Lame, real weak.