Hello everyone! I am new to the site and looking for some help on my next install. I recently purchased a 2010 Silverado 1500 extended cab with the plain-jane stock system (non-bose, no onstar, no steering wheel controls, etc.) that simply isn't cutting it. I want to install a full system with MTX components up front, full range MTX in the rear doors and an alpine 10" type-S sub in a custom box mounted between the front seats. I will be running them off a Kenwood KDC-HD455U head unit and a Rockford Fosgate R600-5 5-channel amp. My question is that I'm trying to determine if I really need the $130 wiring harness that crutchfield claims I need to maintain all the stock features and whether this harness will even help since I am using an amp or if it will make all my chimes obnoxiously loud by running them through the amp. I know GM vehicles run everything through the head unit, unfortunately, but what will I really be missing? If its just the door chimes and turn signal chimes, I'm not going to waste the money I don't think. I don't have Onstar and don't intend to get it while I own the vehicle and since I am running new wires for all the speakers, I won't be using half the connectors in the harness. So has anyone attempted an install similar to mine and not used the harness? I know if I buy a $120+ head unit, crutchfield will give me the adapter for half price but it still seems like an absurd amount of money for some wire and a plastic connector when I believe I can hard wire the few connections I need from the stock harness to power the head unit. Any help would be greatly appreciated since I am about to purchase my equipment sometime this week. As a side note, I have installed somewhere in the neighborhood of 10-12 head units in various vehicles but nothing this new or with all the factory features that are run through the head unit. Thanks for your help!