Wow, I must say you have the record here. You joined in 1999 and only have 3 posts! Wow!
Anyway, to answer you question about using the factory sub.....I installed my Poineer head unit and used a harness from Crutchfield. It came with the harness needed to use the sub. Two wires go to the aftermarket remote sub wire (blue/white) and then the two RCA's plug into the aftermarket sub RCA's.
I agree with you - the factory nav is nice, but damn pricey. I use an portable Garmin unit. As far as head units go, all have their pros and cons. Depeneds on what you want it to do. Apline is almost ready to relase the W-205, but is awesome. I believe you can get the adaptor to use the steering wheel controls. I have the Pioneer AVH-P6800DVD - I went that route as I am in Germany and the navigation on the units would not benefit me as they are loaded with US maps. Hence me using a Garmin.
Not sure about the Sirius.....I'm sure they would work with you.
Good luck with the 07. Pull the trigger!
