Most of the discussion is a repeat of what I said for the Carcomputer v1 so make sure to read that section also.
For the most part what I said for the first CarComputer (see Carcomputer v1) still applies. The only difference now is that I have a big ass vehicle to put the screen in so my little 7" Xenarc is swimming in wide open space. This was not the case in my Contour where a 7" was pushing the limits of what I could fit in my dash. If I was to start off with the Bronco I would probably have a 12" touch screen. Being a somewhat standard size it would probably be cheaper and definitely easier to interact with. Oh well I already have this pimpy 7" Xenarc TSV so I might as well make some use out of it.
Processor / Motherboard / RAM
Here's the big question, are you looking for an ultra low power consumption minute form factor PC that has enough juice to get the job done or are you looking for a standard PC with power to spare? MicroITX (and now NanoITX) boards like the EPIA N-10000 give you decent performance while using relatively low power and generating small amounts of heat. It is also tiny. The price tag is not so tiny however which may have you considering standard PC microATX board such as the MSI K8NGM2-L. If you go this route you are getting a higher performance board (though not necessarily more features) that will require more power and run hotter but has the advantage lots of expansion capabilities and a large consumer base that keeps the price down. In my example you would have to buy the MSI board + a processor so you may not save that much money, if any, over the EPIA board.
I think this component choice just comes down to personal taste. The Bronco has no shortage of space so the size of the board was not a concern. I opted for the larger, higher performance motherboard + processor. I have lots of room to expand my car computer system with this motherboard and if I ever get tired of the car computer I can slap a video card in it and have a kick-ass gamestation.
With that being said I am still sensitive to power consumption, heat, and of course price so a new dual core AMD processor is out of the picture. Instead I opted for a modest AMD Athlon 64 3000 Socket 939 (Venice Core) This processor used 67 watts of power, not the full 89 watts it big brothers at AMD use. You could get some mobile processors intended for laptops that use less power and generate less heat but then the price goes up. AMD does have the Cool'n'Quiet technology which steps down the processor speed to reduce power consumption and heat when you are not fully utilizing the CPU. If you want to take advantage of this feature make sure your motherboard supports it. So far I am a huge fan of this feature. With my CarComputer V2 running in my house on top of a cardboard box my CPU actually runs a few degrees cooler than the motherboard temp (and this is while playing music). Hopefully I continue to get this kind of performance once the computer is in the car.
There is not much to say about RAM. Get the best your motherboard supports that you can afford. I opted for 1 gig of some higher performance RAM. Will I ever notice that I am using low latency RAM rather than some value brand RAM? Probably not, but its not that much more expensive and it comes with heat spreaders. Is 1 gig of RAM really necessary when playing music? Probably not but then again someday I just might be crushing down the road getting GPS directions while listening to music and playing my emulators while simultaneously decoding a DVD to burn to disc. That seems feasible to me so I want to be ready.
I had lots of GPS woes on my previous CarComputer. This time I opted to spend some more time doing research. Don't let the GPS software bundled with your GPS receiver sway your decision.... when you finally use it in your car you will probably replace it with Destinator or iGuidance, but that's a whole other topic. Windows (2000 and XP) sometimes has problems resuming USB devices after hibernation. Additionally USB GPS receivers require drivers. Serial USB receivers don't require drivers and have no problems resuming. It seems that all GPS software is setup to look for GPS devices a serial port. If you get a USB GPS you must install and configure a comm port emulator that allows those applications access your USB GPS as it if was a serial device. This is not worth the hassle in my book. Just get a serial GPS.
In my experience the GPS receiver gets its best reception when it is sitting on metal surface with the best view of the sky. While you might get good reception with the receiver in your front or back window, you would probably get better reception with it the outside of your instead, say, on your roof. Some GPS receivers are water proof and are designed for outside mounting. Get that kind. If you get great reception inside your vehicle, great. If not, at least you have the option of putting the GPS outside without having to dunk it in rubber or something like that.
I whole heartedly recommend the GlobalSat MR-350 (the one I use in my system). Its a weatherproof outside mount serial GPS device. The thing is always locked on with 8-10 satellites before I even get my GPS software launched. This receiver is ridiculously great, only matched by how ridiculously bad my non weatherproof USB Delorm Earthmate was.
If you selected the low power nano ITX mother board route than I cant help you with your power supply. There are oodles of power supply choices to choose from. If you opted for a PC with some hair on its chest then read on. I highly recommend reading the electrical page from the first CarComputer. All the same theories still apply. The CarComputer V2 is even more power hungry than the first (it fits the style of the vehicle its in). If you complete your calculations and determine you need over 150 watts, kiss all those mp3car.com power supplies away. Now you need a full sized ATX DC power supply. There are only a hand full of manufacturers making DC to DC ATX power supplies that put out over 150 watts. Their wattage and line amperage vary. Their price is usually around $200. This is a bit pricier than the sub 150 watt power supplies so score one for those NanoITX boards.
Here are a few links to the power supply manufacter's websites. At some point I contacted all the companies for more info on their units. Some of the people I talked to were absolute idiots, other were over my head. Make sure to request more information before you place your order. Also, unless you don't like useful features you will want to get a fully ATX compliant power supply with a P4 connector.
Switchbox.com.au - 300 watt (absolutely useless customer service)
Zantech.com.au - 250 watt (poor customer service due to a full time staff of wild monkeys)
PowerStream.com - 300 watt (very knowledgeable staff, this is unit I purchased)
MiniBox.com - 160 watt (requires power regulator at extra expense)
Amtrade.com - 250 watts (exact same unit as the Keypower power supply)
Keypower.com - 250 watts (More than enough power for my CarComputer V1)
How will you interact with your CarComputer? A touchscreen is almost a must if you plan on doing anything more than playing music. Touchscreens can make life a lot easier when it comes to navigation software. Touchscreens to have a disadvantage though; they don't provide tactile feedback as to your fingers position. Imagine that there are 6 buttons on the screen. With a touch screen you have to look at your screen to see which one you are hitting. If there was some sort of definition to the button then you could keep your eyes on the road while you hit the button. That is why its so easy to operate your radio while driving, because you can feel around for the right button.
I highly recommend getting some sort of tactile device for operating the car computer if you can. On my CarComputer V1 I ended up using a Griffin Powermate. It lets you assign keyboard buttons to each of its actions. You can twist the knob forward, backward, push it in, or push it in and twist it forward or backward. This was perfect for quickly navigating and controlling my music. Unfortunately it did not have enough buttons to really support my navigation software.
For CarComputer V2 I am planning on ditching the wheel and using a universal IR or RF remote control. Ideally the remote would be small enough to easily be operated with one hand but have enough buttons to be useful for multiple applications. The remote will have to be able to learn other remote's signals as I intend to replace my headunit's remote with the CarComputer's remote. Lastly the remote should be cheap and not too ugly. So far first place looks like it will be the Lola remote offered by MP3Car.com. Its IR, has plenty of buttons (including some that will be great for music controls), will learn other remote functions, and is relatively inexpensive. Additionally it may control X10 devices for future hobby of mine, home automation.