true you can buy the chime modules to keep your door chimes and everything, and yes you can press the gas pedal with the key in the acc position to reset some lights and also pull the headlight switch in and out so many times to reset other lights. but you still lose the ability to change settings easily, such as lights flashing when locking or unlocking using the key fob, which may not seem like a big deal now, but lets say you upgrade to HID headlights. do you really want the HIDs flashing on and off twice everytime you lock and unlock your car? how about when you have to get a new key fob or your battery dies in your fob and you want to reprogram it. can you do it without the factory radio? yes, but its much easier to do with the radio installed. its a wiring harness that runs your radio to the trunk so you still have all those features. it doesnt look trashy at all. no different than having a cd changer mounted in there. in fact its very useful. but thats just one impala owners opinion from another. i think pretty much all the pros and cons have been covered here, so its left up to you now to decide how you want to do it.