Listen to Player and audioholic. Good guys that know their stuff.
I would change out that wire for sure! To save space, maybe put it on the back of the box with some rubber feet to lift it off from the box in case you are worried about vibration and what not. I have mine on the box with out rubber feet and does fine. Other people will say it will ruin it. So that is why I mention the feet. It will clean it up and won't have shit moving all over the place.
Also try to bolt your box down to the trunk. Is not that hard, just need to be careful.
Good luck and happy bassing!