G5 is the new circuit board that is now standard in the JB4. It has more processor speed & memory than the G4 or original board. ISO is a beta system that is being tested that divorces boost control from the stock ECU.
FMIC = Front Mounted Inter Cooler. I have replaced the stock unit for a higher capacity one. I got the JB4 because it best suited what I wanted to do, has the largest user base & IMHO has the best product support.
Last edited by bear-avhistory; 12-10-2012 at 08:44 AM.