Adire has or will have (havent been keepin up on this) a driver that you have the option of having a 48 by 48" radiating surface..now thats big. Audibahn also has a 34" car subwoofer and mtx has a 32" sub, they're both out right now, try fitting one of those in a car. Too bad they suck and an 18" or two could destroy it in sound quality and spl.