Just as a tip, get the harness.
Around here, one cost me maybe $9.99 , comes with nice new clip in connections.
I am one to also make my own everything when I can, but come on, its 10 bucks.
If you have an extra radio harness from another truck laying around or something then I guess I could see you making your own, I just wouldnt recommend hacking the end off and direct wiring it in. Never nice to the next owner of the vehicle to find that
-Chris