I tried a variety of aftermarket tuners on my former '08 Bullitt. All of them caused issues w/the exception of one: STEEDA. My car only had basic bolt-ons but I think the OE adaptive tune really screwed w/stuff. STEEDA had it figured out tho & I had no regrets w/their tune. I've since used only STEEDA on my other Stangs & never an issue on any of them.