Do I need a head unit ?

Hey guys,

I got a 2003 m3 and I want to put a system in it. Do i need an aftermarket head unit or does the stock unit already have a subwoofer outlet ?

Will it ruin the warranty as well ?


Thanks for any help on this issue

No sub out but there are ways around that.

Warranty Depends on problem and dealer

Originally Posted by Officer_Mahoney

Hey guys,

I got a 2003 m3 and I want to put a system in it. Do i need an aftermarket head unit or does the stock unit already have a subwoofer outlet ?

Will it ruin the warranty as well ?


Thanks for any help on this issue

I was in the same boat, wanted a new system, but wanted the stock look of the original head. After doing a lot of reading, the preouts on your original deck are very low voltage. The 4 volt pre-outs on most new head units, will give the amp a much cleaner, stronger input, resulting in better sound at the speakers. I was going to try keeping the stock deck, but I figured while they are installing the system, might as well do the deck at the same time. Cost's less than keeping your head, then deciding tp swap out. They will have to rip the car apart to run the pre-out wires to the amp from the deck. If you do keep your head unit, at least have them run all neccesary wires for a new head unit. That way if you change your mind, they would just have to swap out the head and re-tune the amp. just my .02