My buddy has a pair of E's in his prelude, they sound ridiculously good for such a low power sub. Rear firing is the way to go.
The sound/performance is directly related to the enclosure. All subwoofers have different displacements, meaning a 1cube sealed box with one sub my be .95 cubes net, while another sub might make it .85 cubes net. The driver itself takes up some space and not all drivers take up the same amount of space. I guess if you get the right sealed enclosure and its well built it wouldn't be terrible.
But ported enclosures are different beasts, as tuning relates directly with size of box and size of port, not to mention most prefabs are probably tuned @ 40hz+. A 2 cube box with the same port could have entirely different tuning based on the size of sub. Furthermore, all subs have different optimum tuning suggestions, a prefab box can't take that into account.
prefabs are almost never tuned to what your sub best performs at, and subs are different sizes which means different displacement, which means different net size of the box, thus different output and different tuning.