I used one to eliminate the need for a photo album, so I could use a slide show. didnt work at all. the presentation turned out awful, all the pictures were to be viewed at once.
realistically, an in car computer will run into three problems in the SQ circuit.
#1 is aesthetics. its a pain to make an in car computer look stock! and thats how you are gonna get the most points most easily. Im not saying dont go nuts with the paint and fiberglass etc etc etc! but if you make yoru car look stock, the judge has less to be picky about, easier to get your full points, and everything just looks classier. not easy with a clunky computer!
#2 wiring. the iasca judges are taught to look for wire loom, color coded whether its power or signal or accessory, ziptied every 6 inches with every ziptie faced the same direction, and secured to the vehicle securely. again, realistically, you can get your full points with zipties screwed down to the frame. but think of all those wires! if the judge cant see your wiring job, you lose all your points. even if its the neatest job in the world. travel locations, security, safety, and termination. you have ot have it all for all your points!
#3 functionality. this is perhaps the most most important. if your car isnt easy to use, you lose points. I've lost points in the past for relocating my radio down low. And you can't argue with a judge. Nevermind the glare up high prevents me seeing the radio, located down low has poor ergonomics since I have to take my eyes completely off the road to see it. minus 2 points. so you can imagine if you have to change dvds or cds in the trunk only, or your wiring is a mess, or you have a bulgy carpet, or your wiring is everywhere, or you dont have anything properly terminated (heatshrink gets you more points than E-tape) it can be very VERY difficult to score full points versus your buddy who came with a simple nakamichi radio integrated into his car!
as for the rest of your equipment choice, that wont change your score one way or the other in relation to an in car computer.
my best advice is hide EVERYTHING, be able to change CD's from the front, take pictures of EVERYTHING you cant see, and make it hardcopy! make your car look stock. If you HAVE to eliminate the radio, make sure its really really easy to change CD's, volume up and down, track advance and fast forward, no waiting long periods of ime for programs to load or whatever, you want cd and track navigation to be fast. if you can use an aftermarket in car cd player, hide the screen. its unneccesary baggage.
and have fun, its more fun to take a halfassed car and do poorly while having fun than seriously competing with something that isnt seriously competitive and getting disillusioned with the aspect of SQ!
and if you are really really serious about starting to compete in sound quality, start with some reading about the theories behind sound stage and imaging. MP3 forum here really loves to talk about noise static, recording quality, tonality, etc. But noone here talks about the other factors that affect your in car sound quality that have nothing to do with recording conversion, sampling rates, factors that quite frankly affect sound quality far far more than topics discussed at this forum!
I suggest as an introduction to the theories of a sound stage to check out audionutz' tutorials located over at the www.elitecaraudio.com website. He has many instructive tutorials from "SQ setups and the theories behind them" to horns and AP enclosures, advantages or disadvantages to certain ways of installing, and how we can best optimize our stereo to our listening tastes.
and when he says dont worry about height when setting up kickpanels, dont listen. imaging your kicks centered high rather than simply centered saves you a boatload of work later, I promise!