Rear speakers are not 6.5!
 

I just went to rip out the interior and discovered that my 6.5 two way speakers wont fit in the rear slots. Looks like a 4" or maybe 5". I'm going to try and mount a amp and two 6.5s behind the rear strut bar. Just wanted to let others know.

That's my plan also, let us know how it sounds.

From my experience, the rears will destroy your sound stage if you are really going for an audiophile level install. Invest in a quality set of 6.5 comps on the front and put a 10" sub in the back and call it a day.

I have a set of eD 6500's in my RSX and a 13Ov2 in the back powered by a Nine.2 and Nine.1 respectively and it sounds incredible. Grant it I stripped the entire car with about 3 layers of deadening, had to create custom baffles, and actually drill into the frame to fit everything, it was totally worth it.

I can't wait to see the options eD and others make for the 370z. Another member here already installed that shallow JL subwoofer even.

Ricochet is 100% right on. Rear speakers, especially in a 2-seater are pretty much worthless for high quality music. Rear speakers are for surround sound and fill only and the Z car is too small to need any rear fill. This is exactly what I did when I first got my 350Z and I plan to do the same when I get a 370. I like the stock nav system so I will make that investment but everything but the head unit will get ripped out. I will most likely go with JL Audio for front components and sub with a 4 channel amp exactly like I had in my 350.

So pluckuduck, you don't think it's worth adding some 4" 2-ways in the space behind the seats, along with 6.5's in the doors and a sub in the rear?

No, I would not bother even touching the rear stock speakers. I would just bypass them altogether if it were me.

How about adding some rear spkrs to the stock setup in the base model?

So the base model doesn't have rears? I'm assuming they have the spot though. Also if they didn't come stock with the speakers the stock headunit wouldn't have outs for them (it would be uneconomical). I could care LESS about the stock system as I'm going 100% aftermarket as always with 6.5 comps in the front and a sub in the back (maybe even a few 8" eD's in a shallow mounted false floor this time around?)

The space for the rears is there in the base, and I'm pretty sure the OEM HU has unused outs for them too.

Doubt there is any wiring though.