1) I have a Limted w/ the Bose sub and OEM amp.Huh? Are you trying to run aftermarket subs off of the bose amp? Or are you trying to run an aftermarket amp and subs off of high level input from the door speakers?
If you have a low level/RCA input and power you can use... Then get an amp and subs and wire them up... The resistance/impedience on the sub configuration only matters to the amp for power output and stability of the amp (some amps can only go to 2ohm or 4ohm).
2) I also have a Kicker HS10 self-powered sub.
3) The HS10 can and does run off the Bose mono amp signal wires. (Search the forum)
4) People here with the non-Bose (SE, SEL, SEL Premium) have run the HS10 sub by running power and ground then tapping the signal into door speaker wires. (Search the forum)
5) Based on this theory, I'm wondering that since the HS10 is self-powered--I don't think it pulls power from the OEM amp, just the signal kinda like the door speakers--will it be safe to tap said sub signal wires and run BOTH the Bose and the HS10 sub at the same time.
5) If it's NOT safe, how do I wire it up? Do I use one of the diagrams I supplied above?