Easy - there is a blank rubber grommet about 6" directly above the gas pedal with nothing in it from the factory. People will use it to run the rear speaker kit thru to the front amp. Can't see it from the inside as it's covered w/ sound deadening material. However, when you remove the battery completely from the tray, you'll see it behind there. Just cut an X into the black rubber plug w/ a utility knife and poke a hanger thru it. Then go into the cabin and look directly above the gas pedal for your hanger. Search for a rear speaker kit installation DIY and you'll find pictures.
Also, once into the battery compartment area, run the wires under the cowl towards the passenger side about 18" or so IIRC. Then bring them to the front of the car and you find a blanked plug leading to the frunk itself. Feed the wires thru the plug there (normally used for a CD- Changer) and you'll be good to go.
Post up some pics/details when you're all done.
Good luck
