So, I know HD considers a Stage I to be air cleaner, pipes and tuner. I'm planning to keep my (upcoming) new 2019 SGU under warranty for a few years, so that means using SE/HD upgrades. But how much performance will I actually get paying for Street Cannon slip-ons. Again, to keep the warranty intact, mean keeping the cats too. Is it primarily just a sound improvement, or will I get a some performance? I'm basically wondering if I should save the $500 on the pipe upgrade, for now...