I got a used Fast EZ EFI from a friend for a good price. Installed it in a day and have had 0 problems. Every time I thought it was acting up it turned out to be some other part of the engine. I went from sea level to 10k elevation in Colorado with out missing a beat. Now I have seen people complain about the system on the interwebs but you can only take some of that at face value. Tin kit that bolts on the stock intake and all the cables and linkage hooks up no problem.
Have fun choosing.
Computer, sensors, etc?