depends on the brand of sub. For example, if you have an RF sub you will get a lot of bass in comparrison to say an eclipse which focuses on bass and clarity. JL tend too be somewhere in the middle. Keep in mind, your car is small, so it's not going to take much to fill it up with sound. One sub will certainly get the job done, two subs, if they are RF or just a standard type sub you will sacrifice some clarity, especially when all your windows are shut etc.