I have hmf and its really loud!! I also had a cobra exhaust on my one 400ex and that was the loudest pipe ive ever heard!! fmf is quiet don't get that! c sparks r loud but hmf has them beat! If your looking for the loudest I would have to say the cobra rev megaphone super loud!!!
2002 426ex 11:1 hi comp. wiseco,hot rods crank,stage 2 hotcam,rev max cdi box,ported intake & exhaust,header welds ground down,uni filter,lexx slip on,pro armor tether swtch, ,tusk nerfs,msr quick adj. lever, moose hand guards,moose bar hold down,renthal bars,xrf rear grab bar,moose bar hold down,rock front bumper,DG front frame guard,pep steering stab,alba alum gas cap,covers,HB racing rear brake block off,gripper seat cover,shock covers,custom 426 graphics,,,air scoops,tusk alum. shifter,