shanelu97-Go Eagles!

Have 2001 A4 with Symphony System and would like to start upgrading stereo starting with speakers and adding a 4 channel amp.
Do I need to have the wiring completely redone?
Do I need a line conditioner coming out of the headunit?
Also installing a sub and amp, should I get a crossover?
Love music but not to up on the technical aspects of car audio so looking for help and info

MikekiM@PureMS

Adding an amp will generally require that you run new wires to each individual speaker. The factory wiring is now way large enough to handle the extra power output by a new amp.

The headunit has low-level preouts, when used with the Blaunpunkt adaptor from Crutchfield. Using this will now require any line conditioning.

When installing a sub to any system you generally want a crossover, either passive or active. If you're planning on adding amps to the system, your best bet would be to find an amp with a x-over built in. Saves space and makes it more convienent.