whats the best pipe for a z400? i'm decided between hmf or fmf

 

Do a search if you want to hear the BS. THe truth is that you can get just about any one you want, there is no BEST pipe. the worst pipe dialed in properly will out run the best pipe not dialed in properly. Don't spend your time trying to figure out what is the best pipe, spend time getting the jetting and gearing set up properly.
I have a LRD , I love it , but I have heard the same about both you are considering.