Hey guys, I just bought a 2013 Impreza WRX hatch last week and just as I have been reading the sound system is sub par. I have been working on buying all the components to upgrade the whole thing. I really want to mount a subwoofer under the passenger seat and I was hoping someone might know of one that would work for me. I already have the amp I will be using Alpine PDX-V9 that has 5 channels 4 x 100 W and 1 x 500 W. Any subs out there that will be able to utilize the full potential of this amp, but still fit under the passenger seat? Money isnt really a problem I have about $1000 left in my budget for speakers and the sub. Any good speaker recommendations would also be appreciated.