Here's my opinion on the lower pocket install, since I referenced keep_hope_alive's install when I had my custom lower pocket done.
1. I didn't want to cut or splice any of the factory wiring. The only thing done was remove the factory speakers. Nothing else was changed from the OEM stereo.
2. I wanted massive sound improvement. I've always had aftermarket systems in all my cars. My baseline is always 2-12 inch mid-level subs running 500 watts for bass. I had my 2 JL Audio 12w3v3 subs from my last car, so I used them in the Accord.
3. Removing the factory door and rear deck speakers with the speakers I had in my previous car would provide the mids and highs. This was some work, but nothing more than others have done. The biggest work was around running 14 gauge speaker wire through the doors to not use the factory wiring at all. Second challenge was using Scosche SAHC634 speaker adapters for mounting. These are cheap plastic that required some cutting and drilling to fit. They're general purpose speaker adapters. There are much better options that many have done, I chose the simplest way at the time and may change later.
4. I didn't care about losing any of the steering wheel controls, but I did care about keeping the iMid functions. Really, I just wanted to keep the fuel economy and the system controls. I use bluetooth through the aftermarket Alpine CDE-154BT. I haven't decided whether or not I wanted to buy the module to integrate with the steering wheel. The lower pocket area is so easy to access, it's not missed. Also, the Alpine head unit did require antenna adapters, which I couldn't find my receipt to confirm the make and model of. I think others have posted anyway. I have the Alpine microphone mounted along the roofliner to the right of the rear view mirror. It works great, calls are clear. Oh I forgot to mention, power for the Alpine is taken from the same line that would have been used for the interior footwell lighting.
Everything else is common work. Installing an amp will require you to run power and ground. You need to run speaker wires, RCAs, and HIGHLY recommended to sound deaden. DON'T SKIP THIS.