rolf wrote$300 for something that can totally destroy your engine...interesting :D
For inexperienced people it might, I think you just need a bit of general knowledge of ECU and fuel/spark operations. It is a must have for car tuning and I have some clarifications:
1 - It is not dangerous, it has a supplementary kit called Megasquirt Stimulator, which allows to test the system before plugging into car.
2 - It allows to virtually monitor everything in engine: RPM, temperature, air/fuel ratio/ EGR value, Boost/Vacuum.... Plus it allows to get maximum horsepower and fuel efficiency.
I know I sound like am marketing the product... but am not.. am just collecting info and am gonna build it asap.