Re: What double DIN head unit to buy?
The high end double DINs all have a full face that doesn't leave room for an exposed CD slot. For a budget of $400-500 I would just pair the head unit with a 4-channel amp that has a bandpass crossover built in. Most amps are going to limit that to a 12 dB/octave slope but it's not that big of a deal for a budget active setup. Many passive crossovers use a 12 dB slope.
edit: Factory XM radio is different from aftermarket. An "XM Ready" receiver will have a separate box required to get XM radio working. A new antenna is provided. Sometimes you can stick the antenna to the top of the radio and it will get signal through the dash and the windshield. The best reception comes from putting the antenna on the roof.
The 2012 Pioneer AVH-P3400BH has most of the features you want. The new model replacing that is the AVH-X3500BHS. I don't know if it's shipping yet.
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