the ecu flash just adds a misfire detection to the ecu so it can correct it. if you got a recall as i did its because certain ecu went out without a misfire detection in the stock programming . you will not feel nor does it effect performance.
I was also concerned that I would loose performance after the re-flash but after a few posted on here I went ahead and had it done.
I am here to report that not only did I NOT loose any thing I may run a little better.
I have a small race and obstacle course set up that my son and I play on. On the back stretch I used to be able to hit 68 mph. Now 70 is the number. I used to run dead even with my my son in his Maverick but he is for sure not happy now when I edge him out.
Oh, the dealer noticed that I had not placed the do not carry fuel sticker on it so he did! This thing is a blast!!!!!!!!!!!!!!!!!!!!