Just picked up a new system and was wondering if this is possible: I would be tapping into a wire coming from my stock amp into my aftermarket amp then to my new sub. Would it work? How would it sound? Should I leave my stock sub connected or run them both? I appreciate any advice you guys could give me.

 

1) Best way to do this is to take existing wires to stock sub, disconnect them, then connect a line-level converter (LLC) to them. The output of the LLC is then RCA, which you can send to aftermarket amp. Disconnect your stock sub completely and remove it.
2) Do some extensive searching on CL here to find more info on this topic as questions come up in your mind. There's a TON of info on this already posted, waiting for you to tap into it.

 

I left my stock sub alone and spliced the wires going to that to the new 2 12 jl 3's and it doesn't sound bad ( I have the ML system though)

 

It's nice to hear that, I'll give it a try since taking the stock sub out of a SC is such a pain

 

A few more questions guys, if could find these out with the search.
What's the best way to get to the sub wires in the back of an SC. Do I have remove the rear seats or can I get to them from the trunk? Also does taking the stock sub out let more sound into the cabin because of the hole or not really much of a difference? Thanks again for any advice.

 

It is recommended to take off your OEM sub because that hole acts like a port which would allow the low frequencies coming from your subs into the cabin. That is why on SUV vehicles that have systems, the bass is earth shaking cuz its all in the same cabin.