i have a 99 jetta 3 and i want to hook up a pioneer head unit and my amp and sub ... how could i hook them up and rig them to my cd changer... also, what is the best way to run the wires so they are hidden??

or would it be easier to have them installed by a proffessional???

 

biggest part is getting a power wire to the battery. ive always had to drill a new hole throught the firewall, but sometimes you can find one under teh carpet.
the head unit should already have pre-outs for the amp which helps a lot, if it doesnt you can buy a small part that splices into the regular speaker wires to create a pre-out set. i dont know about a changer though, never used one. easiest way is to lay it all under the carpet if you wanna hide it. you may have to take off some siding along the door but its no biggie. make sure you run the ATT wire along with your RCAs from the head unit to the amp, and the powerwire from the battery (through firewall) and back to the amp as well. i usually just connect the ground to something near the amp, such as a seatbelt bolt of something else as sturdy and thick. but make sure its clean metal, rough it up if necessary. Then hook it all up to the amp, make sure you hook up the speaker wires correctly and you should be set. been a while since i put anything like that in but sounds right. you may look into capacitors too, ive had an altenator kill over because of the power the audio system was suckin down. depends on how much youre lookin at, that was two 1500watt amps pushing 4 15's.
good luck hope this helped