Passenger side firewall wire opening

[relyt120]

I am looking to install a sub and amp behind the seat of my MJ.

 

I have run the maximum number of wires through the grommet on the drivers side of the truck for my remote start and power locks/windows module.

 

Is there a reasonably easy to access hole in the passengers side I can take advantage of?

If not has any one ever cut a hole on the passenger side to accommodate wires? Where/how?

 

It will also be useful to have this so the power wire run from the battery will be sorter.

 

Thanks in advance!