Using Factory HU

[Lowblock]

Hey all, Im going to be doing some upgrading in the X this next week and I plan on using the factory mid/cd player. Now I know how to pull the DSP amp connections and reinitalize the Mid, what I am curious about is the what others have done to get more then 2 sets of Pre-amp out of the Mid. I am looking at the Audio Control Matrix plus piece that would allow me to get a Front, Rear, and Sub RCA output to run a single amp or 4 channel, mono block. Also has anyone used the wiring in the back and solder RCA leads on or have you ran 2 sets of RCA's from the Front too the Back. I want to retain the factory HU as I dont want to spend the time to gut the system, etc like I did in my e39. Any help is appreciated

Also, is anyone selling a factory Sirius module? I wish to add the factory system and then a dice kit to get a bit more out of the factory unit.

Thanks
Dave