05 Sebring Mobile video wiring?

2005 Chrysler Sebring Sedan- Kenwood KVT-617DVD- Sirius Sat tuner Havent installed mobile video before. Im assuming the video and sat tuner would be too much for the dash receiver wires? Wondering if i should wire the brain box and the sat tuner to a seperate 12V source. If i do where would be a good place, i thought about door wires under the floor or the power seat circuit but i am unsure of voltage requirements. Not sure where i should get the extra power from if i have to use other than the dash circuit. The Sat tuner will be in the trunk so i want to plan this out for the least wire run. I have a factory sirius 6 wire cluster running to a factory sirius tuner in rear, i also could spade plug in and use that cluster to power sat tuner in trunk and the head unit, just wondering best place for power for brain i guess. Kenwood brain will be under passenger seat. (Battery, ignition cluster, floor door lock wires, power seat?) If its a specific non easy wire i could use a description of best one to use.

Thats easy enough, thanks