I love it, after reading good and bad reviews I thought I would take the plunge. The car feels amazing on the green mode and how it should of come out of the factory definitely feels more responsive
+1 for washers. You only need a few mm, so it doesn't change the pedal location to much. As previously said, red is a bit much for the wet, but fun to flick it on for a quick blast.
I had the same experience after fitting the lightweight crank pulley. Throttle response was 2x better.
Sold my Sprint Booster couple days later.
It was undrivable even on green. Too aggressive.
However. if you don't want to mess with the pulley - SB is a good way to go. It makes a nice difference when driving, but it makes it hard to ideally launch the car.