I have the Fitech on a built 351w in my 66 Mustang, here's my 2 cents worth. The systems are sold as self tuning with minor setup, which is true but not as simple or quick as it sounds. I think that too many people bought the systems thinking they would just install and go and quite honestly don't really have the additional knowledge to check that the system is actually operating as it should, therefore there have been many complaints that the system doesn't work well. Its pretty cool to have all that data and adjustable parameters but if you don't understand them or know what they affect you can cause problems, then of course more complaints the system doesn't work.The water temp sensor and the O2 sensor that comes with the kit, at least when I bought mine a few years back were junk, maybe a 50/50 shot that they were close to any realistic values that they were feeding the computer, cheap enough to replace. As with any new or electronic systems there is bound to be some failures even with good R&D before hitting the market. The self tuning takes more time than expected, cranking and reving the engine in the garage doesn't tune the ecm. All of the companies have suffered some of the same grips that Fitech has beside their fuel command center, although there are some posts about the Edlebrock fuel command center that are similar, heat is an issue. The lack of improper fuel lines and return lines have created issues, also the improper venting of tanks has caused an issue. While I completely believe they have and are still problems I also know that there are many that work pretty good, mine is one of them. I originally bought the fuel command center to save money, ended up returning it and upgrading to a Tanks Inc take with the in-tank fuel pump and haven't look back. When I drive it I check on what its doing, I still do not believe I have reached my final set tune for optimum but for now the car runs good, starts good and hasn't left me stranded. There is a thread on the Chevelle forum that has almost every comment someone could think of as well as possible solutions to them as well. I am like most people when it comes to buying stuff for my car, I expect it to work the first time, however I have seen enough to know that life, or car parts are not always that way. As far as service, I always received good support when I had questions, unlike credit card companies though they only have a few people to help answer calls, no instant McDonald service from them
