Just to let those considering modifying their USA 2017-2020 Harleys know: using a non-EPA tuner (like the FP3) results in immediate termination of your powertrain warranty, as per the EPA consent decree
. I didn't know about this when I had my Street; I happily put on a V&H O2 Naked intake and used the FP3 and loved 'em both, they were a great upgrade (along with the Nightstick muffler). I've become painfully aware of the warranty issue now that I have a 2018 bike. This consent decree applies to all Harleys model years 2017 to 2020. The S&S Grand National slip-on is an excellent product, and it's 50-state street legal and EPA-compliant, so it won't affect any warranty (or at least, it shouldn't). But the S&S Stealth Intake is not EPA-compliant, and could cause voiding of the warranty. And using the FP3 or any other tuner (PowerVision, TTS, any non-Harley tuner) will cause immediate and irrevocable voiding of the powertrain warranty.
The only safe way to upgrade performance on a 2017-2020 Harley and keep your warranty is to use EPA-compliant parts, and the safest way is to just go with EPA-compliant Screamin' Eagle parts. The Screamin' Eagle Pro Street Tuner is the only tuner device that is allowed under the EPA consent decree. Use of any other tuner (whether by you, or going to a professional dyno tuner) = immediate voiding of the powertrain warranty.
The warranty under question is the two-year warranty from time of sale, and the 5-year or 18,641-mile emissions warranty. If your factory warranty has expired already, or you don't care about it, then hey, mod away. But if you've bought an extended warranty, you may want to consider whether a non-EPA performance mod is worth losing the extended warranty and the factory warranty.