I've had the Fitech on my 66 Mustang for a couple of years now - its pretty nice and I haven't had any issues beyond lack of knowledge. There is/was a thread on the Chevelle forums where it looked like every Fitech that was installed didn't work or had some issues, I believe with any new product that could be the case for many of those that posted but think a lot had to do with not starting off properly in the first place. IMO, one of the biggest problems with these kits is they are sold as bolt on and go and it will self learn, while there is some truth to that it really is not the case and says so in the instructions. The variables each car has creates a challenge as the number of parameters that can be adjusted are plentiful with each separate kit, and while many think they have great skills because they can tune a carb, that doesn't work as well with the computer tuning. I had to make a few adjustments on the Fitech to get stable readings on several things, since then no adjustments, gone through and had to do the same with the carbs. Someone with better skills could come along and adjust both right now and the Dart with the carb and my Mustang with FI would probably run better but they do OK for me and thats what matters. The 750 Holley I bought for the Dart was much cheaper than the full Fitech setup I have on the Mustang and I like both of them - if I have issues with either one I won't be bitc%&ng that one or the other sucks, it will just suck that I am having troubles. Good luck with your choice, I don't think you can go wrong either way, just be prepared to spend the time needed to get things dialed in no matter what direction you go.