lkchris: I've nicknamed you "Negative Nancy".

It would not be a step back, oem efi is all about satisfying the governments emmission requirements, not max power or mileage. The oem setup, like all efi cars I've ever owned, sucks.
Normally I'm a carburator man but this megasquirt deal seems to be a fix for oem efi, and from what I've read so far everyone is happy with it.

Thanks everyone for the tips n links.

Strife: No need for a dyno. Wideband O2 sensor, laptop, and "feel" is all I need. I also have an exhaust temp gauge and G-Tech accelerometer if I need them, but I doubt it.
Getting megasquirt to pass emissions is a no brainer, getting the government to approve it is not. Last I heard (about 10 years ago) it was $100K to submit a part for approval. Not sure if that's 100K period, or 100K per engine type, but I bet it's per type. Can you imagine that times all the engines out there? That's why most aftermarket engine parts say "For Off-road Use Only", it's just not worth it to comply.