I am planning on buying on a double din headunit for my 04 Tahoe. My Tahoe has the factory 6 disc cd changer, bose, rear dvd, onstar etc. I know I have to buy a convertor to keep all my steering wheel controls, bose and rear dvd. My question is what converter or adapter would I need to buy? I don't want a cheap junk one that is going to mess everything up or not work. And how does the converter wire in and what not? I also will be adding 2 12" subs and amp to this if it matters at all. Any help or suggestions would be greatly appreciated!