^ The LC6i (among others) can take those crossed over signal inputs and combine them to recreate a full range signal. Sounds like what you need.

I missed that you have the digital amps so don't need the Zapco processor.

 

Ok thanks - I'll look into the LC6 some more. I'm trying to research the high-level signal that goes to the OEM sub in this car to see if maybe I can luck out with it being full range to the trunk and crossed over somewhere right at the sub. If this is the case I can grab the full signal easily in the trunk of all places with a LC6 and plunk my zapco amps right there and avoid even touching the OEM H/U... that would be too easy though...

 

I would take the signal from the back of the head unit itself, that way you avoid any amps, crossovers, and filters. This is exactly what I am doing.

Also, my clean sweep came with a CD that you play, and it finds the signal to give you a level output at all signals. These DSPs are great at removing all factory equalization.