hi im trying to do some sort of upgrade on my 200 audi a4. i really dont want to change the actual radio but would love to put in a sub. is a sub really necessary if i up in an apm. any suggestions.
It looks like he just wants to know how to connect a sub and amp to his factory HU (bose judging by his screename). I would suggest checking the forums listed below. They will have posts galore for exactly what you are trying to do... or what we think you are trying to do...