Please excuse the dumb question, but what is the big difference between a Pro Chamber and the regular Mac o/r h-pipe? I read the blurb on the Pro3 website, but I thought balancing exhaust was the purpose of all h-pipes. I believe in the "you get what you pay for" theory in most cases, but is the Pro Chamber worth the extra $100. Will it give better hp gains and/or fuel mileage? Does it sound much different? What are the benefits?