Here is a quick video, sorry it's so boring, but hopefully it might help someone in the future. I believe you can tell even through the iflip that the Alpine components are light years ahead of the stock speakers. The sub definitely rounds out the sound and can also just be put under the trunk carpet if you don't want anyone to see it (leaving your car somewhere sketchy, etc).
Everything plus install came out to $1200.
YouTube - 370Z Audio