I have a 96 318i vert and i want to install a system. It is a small trunk and I want to know if one sub would be a better choice than two solobarics. I already have two subs

Advice on how i should set it all up would be appreciated. My battery is in the trunk.

Sealed enclosure, acoustically sealed to your rear ski-pass (don't know if you have one). Oh, ONE will be more than enough if sealed and tuned correctly with a powerful amp.

But if you are too lazy, set it up so that it fires towards the rear of your car. This usually sounds better and will have more output. If you're a huge bass-head, try two haha

thx but if by rear ski-pass you mean the little stash in between the rear seats i do have it. If not i dont know what you mean