check around local. The LMC is nothing fancy, just exhaust pipe and two mufflers. It should cost about the same at a local shop. Plus that way you have the shop to go to if something does not work, you know that everything fits, and you wont have to pay for shipping and the extra money for the large box charge. All the true dual is, is no x or h pipe and you can get into another debate over that. But check local first. Just my .02
H and X pipes help with exhaust scavenging, which is difficult to explain. H and X pipes are both true duals, non true duals would be like an f-body camaro that goes from two pipes down one and then back to two pipes. But I'm sure the main reason for not running an H or X pipe is due to ground clearance because It will need to hang under the transfer case and drive shafts.
Running an H pipe is better suited for the layout under a bronco, just run the H pipe right behind the transfer case. I ran my exhaust straight back right off the headers to an H pipe right behind the transfer case, into mufflers, and ran it just behind the axle with turn downs, oh it is also run above the trans. crossmember ground clearance is not an issue. I dont know how true this is but I have been told that an H pipe will produce more TQ than an X pipe, but the X pipe will produce more peak HP. There is also a noticable sound difference between the two styles.