Pretty much wrong all the way, Rich! LOL
The SD1 is a speed density chip that does not use a maf. It can be run open loop without a wide band, or it can be run closed loop with a wide band. It comes set up for your combination and will run right out of the box. It has 20 plus parameters that can be adjusted altho I only use a handful. Gives you more control of fueling and timing than the normal chips. It's a modernized version of the MaxEffort thumbwheel chip by Steve Yaklin. Steve gave Eric the code for his chip.
The SD2 is built upon the SD1 but it was given the ability to start with the base settings from Eric for your set up and then, using PowerLogger, you can go in and smooth out the A/F tables, etc. just like a modern aftermarket system. As it still used the the factory ecm, it did not have the total flexibility of a modern system but it was a good stepping system for those that like to tweak things.
Bob and Eric both worked on the SD2. They then took that work and started to build their own modern aftermarket system using the MegaSquirt3 and their own software. This gives them the ability to deliver a system set up for your car which would run right out of the box without a lot of set up.
The MS3 is a great system and very nicely priced. William Avila just ran 8.9 a week ago on one, but one must tune it completely to get it to run. Last I checked, it is something like $1300. I think the Eric/Bob Buick Ecu or whatever it is called is more like $1900 with all their software but even a beginner should be able to install it and go for a drive. Knowledge is worth money for the smart, experienced guys as I see it
