I mounted my cb powered PA speaker where you are mentioning (driver side, firewall, above and a little behind the front tire) and it works fine. Out of the elements.
97 TJ 6cyl, 5speed 37" Krawlers on American Racing 17" wheels. (Beadlocks someday)
RE 5.5 Long arm, Currie 9" front and rear with ARB's, Warn hubs and axle shafts, CTM u-joints
Optima Dual Batteries, OR Fab roll cage, custom rock sliders, SMF shorty bumpers front and rear.
My Jeep Site: www.jeffsjeep.com