I don't know what all Jet does to their chips now, but years ago my friend showed me the stock spark table for an Grand Prix and the spark table from a Jet chip (DIS). Well the only thing I saw was they bumped up the spark advance at WOT. That was it. I would hope by now they do more then that, because yes, bumping up spark timing will help, but not as much as an actual tune will, which takes some time to get right. I say if there is a money back guarantee on it, go for it if you want. But be sure you can tell without a doubt that it did add some performance, and if it didn't, send it back for your money back. I want to do a tune on my truck, but later down the road I also want to turbo it, and I am not familiar with the settings in the Ford ECMs.