Car Stereo

Hi all, thanks for reading my question!i have a subwoofer and amplifier from my older car and would like to install them for my new car (toyota highlander). the cd stereo is the original stock, and i have already taken it out of the dashboard and checked what optional outputs it has on the back. it actually did not have a subwoofer output. when i asked car audio staff at best buy, he said that we can use a splitter (i am not sure if it is correct) and get the cable hooked up from the speakers on the door.i know if i take my car to car audio shops, i can get it done fast. but i dnt want to leave my car for a few days because i need to drive it eextremelyday. have anyone done this before ? is there any website that instruct the installation or sell the splitter i have mentioned before ? thank you, all!

Actually, probably 99.9% of factory radios have no low-level outputs (i had a mazda mx-6 once that did). 1) you can use what is called "high-level" inputs that bloke y ( lower-cost) amps feature. this is usually a plug with four wires for connecting directly to existing speaker outputs, usually to the positive and negative of a left and a right speaker. you can do this either at the speakers or behind the radio. 2) connect a high-to-low adapter, which connects like the high-level inputs, but drops the signal to a lower level first and uses an rca cable to connect to the amp.