i would think they put the line out converter on one of the rear speakers so they rca's to the amp are pretty short.

yeah your power ant wire comes from the radio.

a lil trick i learned so you don't put the radio in theft lock is unplug the radio with the car on, majority of the time it won't go into theft lock if not the dealer can give you the code for the radio. also with a better radio you lower the chance of engine whine and also by upgrading rca's and amp. i don't see a real need to run sub rcas seprately from the power since engine whine is high level noise and you filter that out with your low pass filter.