you know, it looks like a subwoofer under the passenger seat there in my 2000 Legacy GT... but, there's never any real vibration there... so what's up? is it a subwoofer? I've got the tweet option and think the sub is in there too... why isn't it moving air? there's a decent amount of bass...

 

good sounding system though... from a jvc mp3 deck... good seperation...

that is a 70 watt sub under there. it does have a gain control on the unit. you may have to remove the seat to see it.

I know it is an option on the impreza line.