A lot of that dealer-installed stuff is pretty easy to remove. It’s also lazily installed. Look for T-taps, excess electrical tape/zip ties, or things that don’t look factory. Start underneath the instrument cluster, beneath the driver’s carpet, look at the wiring in the steering column. T-taps/scotch-locks are a telltale sign.
One gotcha - if they installed a starter kill relay(usually two orange wires splicer inline to the starter wire), you need to mend that. Or you will not be able to start the engine.
