What's the difference with an X vs just straight pipes into the resonators? Also, how loud would it be (drone, etc) with both mid-muffler and resonators deleted but keeping axlebacks?
A straight pipe means no crossover/balancing between the two exhaust banks. That means it's not as efficient, because no scavenging is occurring between the two sides and you will leave a few of HP/TQ on the table. From what I've read and heard, it will also make your exhaust sound a little choppy since each pipe is giving you the sound of a different exhaust bank separately.
An X-pipe is currently the most efficient crossover pipe and will net the most horsepower gain at high RPM, but will also introduce some rasp into your exhaust note that you may not want.
An H-pipe is a less-efficient crossover system that still allows scavenging between the two exhaust banks, but tends to give a deeper and "old-school" exhaust tone. From what I've read, the H does actually give a couple TQ higher in the mid RPM range, but loses out in HP the higher you go.
Assuming you still have the stock mufflers, you'll probably notice almost no difference in sound. Those factory mufflers REALLY suck.
If you do go with either an X or an H system, I'd recommend buying a universal kid from Summit or Jegs and taking it to a shop. The shop I went to charged I believe $160 to weld the universal in, and that was including a foot or so of his own tubing he had to use to cover the distance (I cut out the entire pup-cat to resonator assembly). If you do go that route, stock exhaust diameter is 2 1/4".
2009.5 GT, SRM
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