I am planning on getting a true dual exhaust set-up on my 1996 Ford Thunderbird with the 4.6. I had a guy give me a quote on the plans I had drawn up and when he saw that I was wanting to put an x-pipe in it he said it wouldn't do anything and that an H-pipe would work better. Is this true? What does an x-pipe do? should I just use the h-pipe? Thanks for any info.