The GE also uses a very different timing map... also, the big difference in base fuel maps means you'll be pulling a lot of fuel which means the ECU will be trying to add large amounts as it thinks you're getting less air than the map was tuned for. Stand alone or a piggyback which provides more flexibility than just an SAFC or NEO are the best solutions.... with a piggyback timing control is a must (or add an MSD 6 to the mix). The GTE AEM with the rest of the GTE electronics swapped over would be fine as well but you'll be doing a little more work getting a base tune setup as you're less likely to find someone else whose don it to copy from.
MAFT Pro is a piggyback which offers timing control, MAP/IAT (aka speed density), Boost control, AFR tracking (must also add a wideband like the LC-1 to use this feature).
I've heard of SDS (known of them for a long time), but I've never known anyone who's run one... most of the people I talk to are either very old school or young and think that system is too old school and limited. If their support is good and you can find an existing user base to talk to when you run into problems, then go for it and let us know how it work out. It appears that it can't be connected to a laptop for data logging and programming... this is a serious negative in my book. The small two line black and white LCD won't give you a graph of a chosen value so you can catch the small hiccups... It won't let you review the data from several sensors side by side on a scalable timeline... That's a deal breaker in my book.
Are you looking for easy or cheap?
Screwdrivers to tune a carb? Wow you're old.
