Anyone out there have the 4.0 for their L? Just received mine in the mail and it did not come with the 12" roll of padding for "more lateral stability." What is this stuff, can I use neoprene or some other type of piping insulation instead on the top frame rail? I've contacted the shop where I purchased it and asked them to send it to me since the directions say it's needed for proper installation. Let me know if you guys have anything to share regarding this aftermarket tank & the installation details. Thanks in advance.