wow, so much info, and so much of it wrong...
and the 'real carpc' comment was a little out of line--you are using the OS to define what a real carpc is? Os's are easier to change then hardware--as a IT person you know this.. most define a carpc as something that uses computer hardware-- weather it is a aurdino, or 775 socket motherboard..
1st. CAPACITORS: use in a cars power circuit are useless. they will work as everyone explains them for the first tiny power dip, but after that, they become a parasitic load, and only help the original manufacturers wallet. if you have money to burn, i recommend you burn it before buying a cap..
note: i have been asking, and searching for reasonable evidence that capacitors help car audio systems for years, and, while finding many topics on how they hurt car audio performance, have never come across any documented proof on how they help a car audio system. if you have proof that caps help a system more then hurt, please post up how and why, i am extremely interested in this information.
2nd. i question if you have time for a hobby like this if you say that you don't have time to build a pc from scratch. while many have trouble-free setups that don't have problems, many times, it takes lots of years of tweaking, and tuning to get to that point.. if you don't have the time for hardware, you probably don't have the time for software..
3rd. those car interfaces that you put down are there for a reason. try hitting the 'start' button at 55mph on a bumpy road. by the time you press it, you will have lost concentration on the road for so long, it would be a miracle if you don't hit anything..
4th. AG coatings will many times increase glare-- because they diffuse the light across the entire panel. so instead of just a small part of the screen being blotted out by the sun, the entire screen becomes un-readable..
5th. power-- read up on the different power supply options. there is a good option for that board, and i have listed all of those different options in the past posts.
6th. 8" screen. check the fabrication area. there is no way to fit this in your dash without a lot of work. for a bolt-in solution check the bybyte kits.
7th. gps. check out the bu353 reciever. it is a very common, reliable, and trouble-free solution for gps recievers.
8th. battery/power. for just a atom based carpc, no upgrades are necessary.(the atom is something like a 15w tdp processor-- it is like adding 3 phone chargers to your car..)
for car audio, it depends how crazy your going-- a simple 100-200w amp/sub combo really doesn't justify huge upgrades.. a 3,000 watt system would require multiple alternators, and batteries, and doubling up on the big-3 upgrade...
the big mistake that everyone makes is the connections. with good, solid connections, you can get away with a lot more then a shoddy installation. my system has a alpine 150w rms 4ch amp, and a 300w rms sony amp, and a upgraded battery ground.. even cranked, i have zero dimming issues..
for a eq, what are you looking for?