In searching and reviewing many of the posts regarding the aftermarket pipes for the 07 WR450, I found many of the posts helpful and informative. I am seriously contemplating a full header pipe system and am leaning toward either the FMF 4.1 Titanium or the Pro Circuit Ti-4 Titanium. I ride in Costa Rica and want improved power and need a pipe with a removable spark arrestor. Since I am not subject to noise restrictions, a bit more noise is helpful for safety. Many of the trails that we ride are cattle paths in the mountains and the noise tends to keep them from being a hazard. I appreciate anyand all opinions on these pipes or others before I right the check. I also appreciate any and all opinions on going with slip on versus full system.