Drastic change in sound with headers?

Pretty much what the title says. Im thinking about getting a new set of headers after the holiday. Thinking about the unequal link bbk 1 5/8 chrome headers. I had just replaced the stock h pipe n mufflers with an offroad mac h pipe and some random imported free flowing mufflers. the mac and mufflers are both 2.5 inch. And im just wondering how drastic does the headers change the tone and loudness of the car? Also a little further down the road after the headers im gona replace the stock tailpipes. does the tailpipes restrict that much of power and sound?