Additional Amp Location G23

[blueroom]

I have the JL system on a '16 G23 and replaced the main compartment sub with a Roswell box and sub. I would like to split the sub amps, keeping the stock drivers side sub on the stock amp and adding an additional amp for the Roswell sub. The current amp board is full and there is no room to add a sub. I don't really want to mess with whats there, so I am wondering if people have added an amp without changing up the stock amp board. If so, where did you mount the additional amp?

Bonus question... Should I just Y off the existing input or can I use one of the unused Zone A or Zone D outputs on the Polk unit?

Thanks!

[Rbt]

What speakers is the small amp hooked up to?

[blueroom]

Thats the stock sub amp