i while ago i saw a powered subwoofer that could be installed under a front seat? any idea what make / model these are?

peccy.

 

Don't get your hopes up too high - quite a few companies seem to make them, but they're not very good!

 

There was also something called "bass shaker" that bolted to your chassis and tried to shake the knackers off your car.

 

...try scoobymods.com - I just saw something on there. Looks a useful site!

Nick.

 

Kenwood do one, it's been on the market about a year now.
I heard one fitted into the boot of a 306 and was quite impressed.
It uses a 13cm driver (i think) and a passive radiator.

 

That's the drawback, the in-the-boot thing - the ones that are meant to sound good under the seat actually sound considerably better in the boot!

There are some that fit into the spare wheel, so take up no (useable) space. I imagine they work pretty well, and the ones that I have seen have the amp built-in too. Might be worth a look?