ORP/HFC Will not make a big diffrences its more removing the resonators that an issue. I have the stock muffler and a HFC, I like the sound but cops that go after "tuners" will now pull you over because your focus doesn't sound like any focus they ever heard! Which I am like you I had a 93 Cobra, with Flowmasters America 45 series, louder then my focus ever! But never been pulled over, was with my friend in his 07 GT with Pype cat back stright and a cop pulls me over and not him "laughs"
176WHP/147TQ Running Rich at flat 12! More power to come once finished!