Nexus 7 Tablet Install

Hi gents, I have been planning to do a 7" tablet install in my car for a looooong time now. After a lot of research I decided to go for the Nexus 7 (2012 3G Tilapia model), it has pretty decent specs and they go for about R2500, which is a decent price for what you get. I won't be going into too much detail of the build, mainly due to the lack of pictures and because there is quite a lot of other builds online and they all follow the same basic principles. Here is a short breakdown of the components and some more info:

Car: 2003 e46 330d (with oem widescreen navigation system)
Tablet: Asus Google Nexus 7 (3G) "Tilapia"
ROM: Timur's USB ROM
Launcher and GUI: Nova Launcher (set to 5 rows and 10 columns) with Desktop VisualizeR (for custom made buttons)
Bezel: Double Din bezel from ebay
PSU: 3 amp USB power supply - connected to radio fuse
Sound: Stock front speakers and pioneer 250w 6.5" at the back, powered by a 4 channel Starsound 1800w amp; Custom 49l sealed enclosure with one Pioneer TS-W307D4 subwoofer, powered by a 4000w IcePower monoblock
Cables: Custom DIY OTG Y cable for charging + OTG Host mode, Stinger RCA Cables

What still needs to be done:

USB Hub
USB DAC Soundcard - for cleaner sound
iBUS integration - for Steering wheel controls
Rotary knob for volume
USB ports inside car
Sim card for 3G

Below are some pictures of the install (excuse the bad quality of some of the images, will take better ones once the install is closer to complete)

The 4 channel amp is nicely tucked in where the old oem nav computer and tuner was, I tried to get the monoblock in there as well, but there simply isn't enough room..