I bought into Larry Meaux and even more so Calvin Elston's discussions about reversions on the exhaust side. I didn't go for a specific anti-reversion part, but in 2016 went all out on the small diameter tubes right off the head and the getting all the section lengths close to the numbers pipemax indicated. I *think* its helped. Car seemed happier but I didn't have time to try to quantify it. Logger was out, no time to mess with stuff and I needed the car, so just drove the heck out of it. :)