I would not accessorize, too much, on the exterior.
Flowmaster 50 or Borla muffler. 3" tailpipe, hidden, route under pass. frame. Stop behind hitch cross bar.
Alarm with ignition kill.
Pop-n-lock tailgate lock.
Autoguard hood latch.
Stant gas cap lock.
Mcguard wheel lug locks.
Gm spare tire lock.
Add bass speaker and amp. Use stock setup, maybe upgrade door speakers.
Wheels and tires, when stock ones are wore out, make some truck payments, first.