also trying to stay on topic,
I have a single 10" sub in a sealed box being powered by a 700 watt amp...
now as for power and signal i did NOT run any wires at all... first my factory power antenna did not work so it was removed, I disassembled the connector for it, saving it for when i do replace it, and wired up my amp using the antenna power wires and then i took the rear speakers and spliced the wires for the line level input to the amp... now i have a sub on a dash switch... i am using the factory radio... also i do know what i am doing as far as restricting the power to my amp, i dont need all 700watts... it sounds great and i dont get any dimming lights when the bass hits... also by doing it the way that i did i had to cut 0 factory wires.. I just built myself extensions to plug into the factory wiring and provide me with both power and signal to my amp...

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85 mercedes 300D-T 258k miles