Originally Posted by mellonas
So went by an audio shop down the street and they said all they would have to do is plug a new amp into the old one to run the new subs. I had an old pathfinder with the bose audio system and it had its own amp and i ran subs through it for like 8 years so Im sure this would be just fine
The problem as I see it is that our Sony sub is not just a sub. It is also the DSP. There is no sub feed from the HU. Also our system chokes down output the higher you turn the volume to keep distortion from blowing the stock speakers.
To get the volume / bass you are seeking, you need to eliminate the Sony sub and replace it with a good DSP + amp + bigger sub(s).
I haven't found a viable solution at a price point I'm OK with yet, but I'm still looking.