I have the 12k and like it. I have it in a .8 cu ft box and its does pretty well but needed a lot of tuning with the x over to get rid of a peaky responce with a fast roll off. Now it plays 20 hz with only 250 watts with authority. It is a hatchback though in a sedan in the trunk may need 2. I have herd the 10 o's from ed and was very impressed but a lot is proper tuning and box. Cant go wrong with id either great company great products. Those were my choices the idq (or arc that is basically the same) or 12k or 10 o.