I will be going with the H pipe, my first car 85 mustang GT I had a muffler shop build me a H pipe and with 2 chamber flows dumped on on ground. It had a patent type unique sound only the 5.0's sound the best on. I have not read many good articles about the x pipe. I don't like to buy them prepared, they are not worth the cost and I would bring my car to a local exhaust shop. It sounded great even before I installed the long tube hook headers. I will be with the H pipe please note, they are the best with 5.0's. Unique sound. The X pipe I have ne experience on so I rely on the best. It doesn't case must at your local muffler shop. dumped into the ground creates a unique sound of its own. Please note make sure the H pipe is in charge an, check over the installation. make sure they didn't leave any cutes and hones into sheet metal of car etc.