Not easy to find a powered sub that fits under the passenger seat but as I have a Blaupunkt head unit I thought I'd check their range and found this one:
http://www.blaupunkt.com/en/nc/products/car-multimedia/loudspeakers/products/single/5383/it fits under the Recaro (plus) passenger seat, just!
Couple of DIY mecanno type brackets to secure it to the seat fixing bolts and very simple wiring, only needs +12v, Gnd and subwoofer signal, no power up signal needed. Or you can use the high level speaker inputs.
It does lose a few inches of foot space but who bothers about rear seat passengers in a coupe?
Sounds great, fills out the bottom end perfectly. And only £120 inc. delivery from Germany, ebay item # 390789830187.
