thats normal. same thing happened with my JL w3s. they sound fine with the trunk closed, but when the trunk lid was open, they sound crappy.

i THINK this is due to the enclosure that the trunk creates. bass from a sub is moving air, when the air is contained inside a cabin, i guess it sounds good. when it is exposed to infinite space, like when the trunk is open, all the air is escaping. am i making sense.

and having that divider is normal, and actually better than 2 woofers sharing the same space.