I'm looking at putting this Nav HU in. With it, I'm putting in Kicker Components (all doors) powered by RF 4ch amp. I'll also be replacing the Bose sub with a stealth JL Audio Center Console, powered by a RF 501db. The installers are telling me that the OnStar would be difficult to keep in because it needs the factory speakers and won't go through the after market ones....not that this matters, I don't use OnStar anyways. I'll be putting in the steering wheel control module, bluetooth, and the iPod adaptor. Does this set up sound good, or should I be considering other things? I'm anticipating that it will be sounding better than the factory Bose setup.