I知 new to building cars, and I知 trying to learn about exhaust. Instead of buying a full exhaust system & calling it good, id like to create my own custom exhaust set up. I recently installed Megan racing test pipes onto my g37 coupe & because of the amount of rasp that came with it I知 trying to find the most effective way to reduce rasp without reducing noise level. I want a pretty aggressive & loud sound. I was looking at different Y pipes but then i came across X & H pipes. What痴 the difference between those 3 pipes? What do they do different than eachother?