I also own these SP6 ear plugs, and they are GREAT. You don't have to take them out at all once done riding, as they don't block low-level noise. I have had phone conversations with them on without any issue. They are also super comfy, so you actually forget you have them on. I was skeptical at first, but they are really worth it. I don't think the Ninja is particularly loud (in stock configuration) but my other ride is very loud (Ducati Monster with twin Termignoni carbon fiber pipes) and these suckers dial down the noise nicely. Once I upgrade the Ninja (probably going with the M4 slip-on, mostly for looks and sound) I am sure I will be using these EVERY day.