Patrickkc- I m understand that you are trying to get the factory sub. But in all honesty that factory sub was tuned to work with the dsp system. Meaning 1. it doesnt put out alot of bass. 2. you sare going to over stress your non dsp amp. The DSP amp size is considerably larger. 3the sound quality that it will output will be of level of a 6x9. Unless you are dead set on this project. I would go aftermarket sub. I know how it is to want everything factory. I bought a dsp amp just so i can have the option when i retrofit my navi. I could go upstairs and wire my harness together for you so you can see the sub wiring it is all part of the DSP with navi main harness. it is a black connector that you are looking for

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E53 06 3.0i

wishlist
Comfort Seats
speckdock 2.5

Mods
Air suspension - wip
skid plate replica - in box
OEM sunroof deflector
OEM bluetooth streaming
navi,dsp,tv retrofit - wip
Low prof roof racks
2 directtv satelite tuners
Grom audio usb2
quarter and back window sunshades
2 10"subs- boxes opposite sides/Alp MRP-M850
rear heated seats retrofit
rear footwell lights retrofit
remote window roll up