I don’t know anything about the science or theoretical aspects of this, but I will share my experiences and impressions. After adjusting the spoiler, although I appeared to lose 3-4 mph in top speed on the back straight at Road Atlanta, my laptime fell off by a second or so, perhaps only because, psychologically, I felt more comfortable taking faster turns,including the infamous T 12, faster. Or it could obviously be that the spoiler helped mechanically in that respect. I also sensed more stability under heavy braking. I don’t switch the angle back after going to the track, and I have noticed a decrease in my mpg, fwiw. Hope this will be helpful, but while you may want more anecdotal evidence, you could always just try it and see. It is not a big job to reverse. Also, in my experience, the slightly increased elevation of the spoiler is not detectable in the rear view.