So here are my thoughts on this after doing a lot of reading in regards to the AV/and HU topics in this forum. BigAudio is one the best resource guys on here to get acquainted with. I would like to get into his status on here in this regards soon as well. I'm an MECP installer on the side here in DFW, so I will share what I have found so far.
1. Bose - in all my years of installing and using in Home and Car = Buy Other Sound Equipment has been the moniker for years. Dont' waste your time on this equipment for the money. Invest wisely and in other brands. Kenwood, Alpine, Pioneer, Eclipse, Boston Acoustics, MB Quart, Infinity Kappa, Polk DB, just to name a few.
2. All Single DIN units will require the Sleeve by Metra or Scosche to be installed , which will feature the pocket unless you wish to go into some heavy duty style fiberglass enclosure modifications to your dash. Most of the time, the average user will not do this. For most of all the DD or DoubleDIN units, they will fit with OEM screws (TORX) in the factory location. I have NOT confirmed the exact units which will, but I can say that anything 6.1" Screen size or some of the 7" will fit just fine.
3. As for the BASE model with speakers, they are a short depth speaker in the doors, and no tweeters in the dash, no speakers in the rear. The solution for this , would be to upgrade your doors with the adapters to fit, with a 5 1/4" if my memory serves correct, 2 way (cheapest) or 3, 4 Way speakers (bit more in cost) brand as mentioned above. This will greatly enhance the sound you hear when coupled with a good unit in the dash.
4. If you wish to add any of the additional types of speakers, you will need separate amplification and enclosures unless you wish to modify the panels existent in the rear of the 370 as it stands. Best recommendations for Amps would be anything 4 channel to power the speakers which don't include a Sub. Dedicated 1 mono block digital class amp to the subwoofer alone, which allows for discreet power and channel signal from the HU to the AMP and then to the SUB = Least amount of interference from other speakers and having to 'channel' down the signal coming into the 4 channel amp say you power the hypothetical REARS on channel 1 and 2 of the 4 channel amp, and then bridge 3 and 4 channels to power the sub with a low pass crossover to ensure no highs hit the sub. These are both ways to do it, however the cleaner signal way is 2 amps , 1 to power the 2 rears and the 2 fronts in the doors (4 Channel Method) , or 1 AMP to power the rears you install, leaving the doors to be powered by the HU - (2 Channel AMP Method), and the installing a Single Monoblock Digital AMP for the sub.
5. If you wish to do any of the DDIN units you will need to understand that you will be tapping in most cases the speed sensing wire, which there are many of posts on here which I will link to later when I'm on my mac as I dont' have them bookmarked on this machine. Tennessee has a great
tutorial on install for Single DIN, and AK370 has a great one on the D-DIN unit which Big installed.
6. Wires to be tapped to get features to work - Orange Wire at either the driver kick plate or rear trunk driver wire bundle for Reverse Sensing Engagement - (HU Wire will be or should be Purple / White) , Yellow Wire in MS80 connector, pinout 18 in the Factory OEM harness will be where you connect the aftermarket HU speed sensing wire. If you wish to use reverse camera backup , follow the instructions on AK's install for guidance, it's the easiest to follow and the cleanest. (if i mispoke on the wire colors, the family here will correct my post and I apologize if it's in error). All the other wires in the Aftermarket Scosche NN04B Wiring Harness or Metra Nissan 2007 - Up Wiring Harness will be pretty straight forward in solder or butt connections (wiring codes are on the back of the bag which it comes in)
7. As for the slim line types of enclosures and subwoofers, I personally have not used them however in my years of installing, they are often not a chosen item, only because the sales teams i have worked with understand the physics behind the motion of sound and displacement of sound a crossed a medium (IE the speaker baffle which is the cone). When you cram low frequency sounds into a small enclosure with no room for air to travel, your sound becomes very tight and not full in the intended fashion that a sub-woofer is supposed to emanate. This being said you don't need a large band-pass box with everything to get that sound. Doing like Elan has mentioned above, creating plug and play type connections for easy removal is your best idea. I would personally recommend a 12" in a front facing box with a aforementioned amp scenario which would do the trick. Just cause you sacrifice space with design by a manufacturer for a sub, doesn't mean you won't also sacrifice sound and clarity and correct replication of low frequencies from the song.
Lastly, Feel free to reach out to the people on here like AK, TenneseeZ, BigAudioFanatic and myself if you have questions. These guys are always willing to lend a hand and information as i have noticed on other posts and even my own. I just recently installed the AVIC-X930BT in our 370Z and just had to find all this information, which some questions asked i was able to get everything i needed from the above guys. It's a great resource and family here, reach out if you need something, and remember in most cases, no question is a dumb question. Part of learning and understanding is asking questions. ;-)
Hope this helps.
-Osirus