1- You can handle a car with 500 HP? Right. What have you driven that was even close to that?
2- I know you won't listen, but don't spend all your money on a car. If the top of your range is 15K, spend 10. I know you're a guy (and a kid) and cars are the COOLEST THING IN THE WORLD... but it's just a car. It will probably get wrecked and/or ruined by you or your friends, so leave some money for yourself, not just the car. Also, don't lease. Ever. You might as well just throw your money in the street.
3- You can't get a good BMW for less than 15K? Not that I condone 16 year olds getting BMWs (or nice cars in general), but c'mon! FYI, I got mine for $3940.00. Which is considerably less than 15K. Also, my father bought his 2001 530i w/ Sport Package in Anthracite Metallic (not a scratch on it) for 14K. Granted, he can Jew some people down when he wants to.
4- Lastly, I'd recommend a Jeep. Why? You can run off the road, drive ANYWHERE and get into a bunch of mischief with one. I wish my first car was one. Turns out, I got a Saturn. But that's not to say that I didn't off-road in the Saturn.