Alot of people run sealed as its easiest to build, change. I run twin 12" JL subs through one large sealed box in the clio and its more than adequate with 500wRMS. Depends what your after. ie space, SQ, loudness. Read the guide in the 2nd post and decide its all down to personal choice. With the clio being a small tight space audio wise a decent amped 10" or 12" sub in a sealed box should start you off well; Cheap, compact with a nice punch to it. In time you may want to chop and change your setup. As said everyone likes different things so dont take one persons opinion as the only option :approve: