Dude, think of how many chicks you can fit into the Explorer!!! I am 21 years old, all my friends have crappy 4cyl cars, and hate them, I went for what I wanted, and could afford, which happened to be my Explorer. I am not trying to sway you, it is your decision, but if you have something that is reliable, and gets you from point A to B, then keep it. If your friends laugh at you, it because they are jealous!

I think that denial is a good way to live, when you cannot afford what you Really want. Which for me is a '95 F-350 Dually with a 7.3L Diesel!
Since I sort of went off in the last part, also keep in mind many parts are swappable in the Explorers, so you can upgrade yours for VERY cheap by taking a few parts off of one in the Junk Yard.
If you do plan on doing a Stereo just hit me up, I'll still help you out.