talking with several exhaust shops that have done work on multiple race cars, i have come to the following conclusion: h pipes are best for cars with chambered mufflers and x pipes are best for cars with flow-through mufflers. to locate where to join the two banks: with a wax crayon, draw a very thick line down the pipes starting after the header collectors for three to four feet. allow the car to idle for several minutes. tie the pipes in where the wax melts/burns the most. if this is correct, im just passing along wisdom. if im wrong, (it wont be the first) correct me so i can learn from you.