If your mpguino is working, you don't "have" to do anything. The subject of programming gets exponentially complicated from there, but if it isn't working at all and you don't have the facilities to reprogram it, then send it in with return shipping for reprogramming, for 6 months.
This is the bare bones mpg gauge, meant to be tossed onto the dashboard and used, not designed for development/programming/updating but the chip is socketed so it is not hard to reprogram it:
http://ecomodder.com/forum/showthrea...html#post75195
re: blue LCD, tried them, lots of glare, harsh at night. The yellow green ones have the best visibility under the most conditions after trying lots of LCDs and doing lots of testing with this model, so that is what I ship. Not enough unit volume here to get into a lot of hardware options here (each option requires testing too imho), but I can leave the LCD unsoldered if you really want to use one of your own choosing. Just make sure to communicate that.
P.S. this uses a standard 3.5 floppy power connector if you are looking to put plugs in multiple vehicles and have an old power supply handy.