I did the same thing Grant did, except I did it with the tower on. When you get under where the legs mount to the hull to drill that out, be careful of the falling debris (metal/fiberglass) this can easily get into your eyes (WEAR SAFETY GLASSES)if you do it the way I did.
I also ran the speaker wires up on one side (passenger)and the lights wiring up the opposite side of the tower(driver). This makes it easier for wiring and switches. Another reason is it will eliminate the possibility of any noise that could bleed into the speaker wires from the power wires. It is also alot easier to pull the wires because there is not a large bundle of different wires. Your holes will be smaller too.