Depending on your budget, there's a couple of different options. I ended up using Duplicolor's version, using a $10.00 undercoating spray gun from Harbor Freight. As other's mentioned, it's all about the prep work. Do a crappy job on prepping the surface, and it's not going to stick too well. The nice thing about spraying it, as opposed to rolling it on, is that the texture ends up a bit nicer. Line-X would be nice, but its $$$...