Your car is nice because its a 350z.
It's obvious that your into look more than performace. This is your taste and we shall respect it.
That being said heres MY opinion.
It's a shame to add dead weight by installing 3 subwoofers. I would install only one 10" high quality sub, smaller (lighter) box and smaller/fewer (light again) amplifier.
And getting back to looks, your wheels are bling but sunk. Theres still space for better offset/larger wheels both front and rear on your car! (if it was for performance I wouldn't complain about the wheel flushness before knowing the specs and compare scrub radius / kingpin offset)