I bought a Bass Boss 10" and while the sound was good, the amp was too sensitive and I manage to blow it. They offered to repair it but it was cost prohibitive to send it back so I pulled the amp and powered it with a decent amp. BTW,I put in in the caddy under the hatch floor but it could have gone under the passenger seat (just barely).
I posted this like a day ago, it is just my experience with an underseat unit; :rockon: I installed a Kenwood KSC-SW10 back in January. There was (is) still the thread. For ease of use, anyway this is a unit that will fit under the passenger seat without a problem (I have a 2011) I think almost everyone agrees that the sound in the Prius sucks. While replacing all the speakers and sound system would really be the way to go, it's just too much work and too expensive. I did have this unit installed as I'm none too handy. Adding this sub has been a major improvement in sound and the install is invisable with the extra sub-woofer control in the glove-box. It does not interfere with the seat. The unit I thought costs around $125 but when I went through Froogle it lists at about $150, as I recall the Pro-Install was $100
I am not picking on you all with II/Two's but I don't think that there is much room under the seats on models III/Three thru V/Five to put a sub. I have crap under both of my seats I think on one side there are Nav. and ATP boxes and the other side is the JBL amp.
things to think about I guess, since the HU has no preouts, you need to run transducer that take the speaker wire to rca outputs so the amp can deal with it, then run the speaker wires out to where you want then to conect to harness or the speakers themselves. A HU with RCA outs, have cleaner sound and less distrubance in the force.Easier on the amp.
I already had the earlier version of the Kenwood KSC-SW10 (called the KSC-WA62RC, or wOOx) in my Nissan Frontier, so right before I traded in the truck I had it pulled out, then had it installed under the front passenger seat of the Prius. Both the old and new versions have speaker inputs (and well as line inputs), so you should not need any other electronics to make it work. In my Frontier I also had a Kenwood HU, external EQ with sub control, and separate amps for the front and back speakers, so the factory system in the Prius is definitely a step down. But the sub does help fill out the low end. I'm still fiddling to get the best balance between the bass level settings on the factory HU, and the crossover and volume settings for the sub. It can either sound too "boomy" or too soft until you hit the right recipe. You should run tests with a variety of artists and genres to get a good average configuration set up.
The sub is fine. Again, not as good as the entire Kenwood system in the truck I traded in, but the sub does fill out the low end when used with the factory system. At some point down the road, after I've saved up the cash, I'll probably swap out the head unit with another touch screen unit that has a good interface for the iPod classic, sub-out, and enough built-in amplification to properly drive the door speakers (assuming there's also a steering wheel control mod available for the unit). But for now, this is fine.
