I have rear and 1/4 window louvers on my 2011 and dig them! 🤟 Not everyone likes them, but I do. I also painted the stripes on them as well. I’ve seen some 2015-2020 Mustangs with some angular plastic louvers... I don’t recall seeing one with traditional louvers like on my 2011. I do have a little project cooking for my 1/4 windows, but no plans for the rear window at this point.