The FMF is what came with my Zilla when i bought it. It has great low end grunt but from there the LRD out performs it by a lot. All i see about the LRD that it is old technology and that the new pipes are out performing it. By how much ? The top dogs want $800-- $1000 for there pipes i only paid $400 for my LRD. Am i really getting that much more power for twice , or more, the money? I am not a racer just a dune rider, but i do crave big power.