So how are you running an aftermarket amp ?
 

Ok so i would like to get the 4080 enclosure, but would like to know if anyone is using the signal going to the factory sub amp for their RCA input to the aftermarket sub !! I wanted to splice into those wires to go to RCAs !! Any help ?

I tapped on to the line going from the Bose Amp to the Sub Amp and it works great for me. I am using a JL 500.1/v3 amp. Bought the RCA's and cut one side off and soldered the ends to the signal wires.

Ok cool i was wondering if the signal from the bose amp to the sub amp was clean and would work ...im gonna use the same amp so thats cool i guess i will be good then !! Did you use the turn on signal to the sub amp for the remote ?

Yes. I did. But some one else tried it and it didn't work for them. But he was using a different amp. I think he said that it was only 6 volt trigger not 12 volt like normal. But since you are using the same amp as I did it will probably be fine.

I am going a different route, although haven't gotten to the stage of hooking things up yet (still building my box). But I have tapped into the signal coming out of the sub amp and am feeding that signal to an MTX ReQ which should take out any of the processing of the Bose system, then feeding into my sub amp (Rockford 300-1). We'll see how it works.....

I tapped in to the rear speaker input directly coming from the head unit to the bose amp.

Also the trigger wire used for the bose subamp is 10v, it will work on some after market amps and it won't on some, depending on how forgiving the trigger is on your after market amp. You might just have to run a wire from the front that has 12v (which is what I did).

What you did works, but you can also take the 10v and bump it to 12 volts with a relay... see this doc. (http://www.installdr.com/TechDocs/999404.pdf). The part about "Allow A Small Voltage Wire To Control A High Current Power Wire on page 3.