I have an AEM EMS V1 on my galant. I guess it really depends on your understanding of engines, tuning and computers.
For me, it was very easy to catch on after TheBoz (Keith Boster) explained a few things to me. The hardest thing is getting the idle but after reading the manuals and various online threads, I was able to get mine to idle fine without the IAC.
I plan on buying an AEM EMS V1 for my supra real soon too.
I guess my only grip is my AEM EMS reads the wideband off by ~1. I am not sure if I assume the gauge is right or the AEM EMS. So far I assume the gauge is right and then offset the AEM EMS. Any thoughts?