I have a 1 ohm factory sub in my Lexus that I want to run directly to my 700BT, is this possible using a cable such as this

http://www.radioshack.com/product/index ... Id=2102959

I bypassed the factory amp and replaces both front and rear speakers with aftermarket and ran all new wires as well.

if by using that cable plugged into the subwoofer out on the back of the deck then you wont get anything from it as pre-outs are made for sending signal to an amplifier, they do not provide any power. you need an amp, and a new sub at that,

+1 you will need an amp, if you find the right amp, and you like the factory sub sounds, you can just install a new amp for that sub. 1 ohm stable = not cheap