Mine is 2010 Myvi, but similar situation.
HU is Kenwood 2Din model.
Speakers front and rear are Alpine 6" & 4", straight swap for OEM type (Massive difference)
Kenwood KSC-W11 underseat subwoofer installed under driver seat.
Notes:
1)Note that battery is only 40AH standard. Anymore sub+poweramp is going will take a toll on battery and alternator. I prefer to retain standard battery. Bigger batt is getting expensive everytime to change. I have measured the current demand of power amps. At idle its around 1.8amps..but when big bass kicks in, it can be up to 10-20amps..up to HALF the capacity of your battery and tax your alternator. If you have a say a Proton Persona battery with 100AH and big fat boot space..then different story. Add all you want.
2) I thought it over about all those powerful 12" sub + amp in the boot. Take up space for sure because I travel often. I don't need earth shattering bass within the car.
3) Underseat sub was the best solution to meet my requirement and not tax the battery anymore than it should. The sub is just enough to fill the bass void and compliment existing speakers for a full bodied sound at comfortable volume. Thats all thats needed for me. I listen to hifi at home and maintain similar sound quality without going overboard at the car.
4) I'd rather spend extra cash on better TYRES..not audio. Ride comfort and less tyre noise also contribute to better audio. I'm just being practical and prudent without overkill for Myvi. I treasure my precious ears too.
This post has been edited by bsl555: May 16 2015, 11:21 PM