The Megasquirt wasn't wrong. It was working well enough, but it wasn't able to provide any higher level diagnostic functions, effectively run the IAC valve, run drive by wire, or integrate a comprehensive traction control strategy. My tuner was also moving away from tuning megasquirt, and as someone who relies on a tuner, I figured giving him want he needed to succeed was important. The Megasquirt is a powerful computer than can do a lot, but I was running into those limits. The Haltech also provides a lot more I/O functionality, which I was out of on the Megasquirt.