thats good dude, glad it worked out well for you. i perfer HMF, i have a full system on my 250ex, and man i felt the difference like no other, HMF is really loud tho, def on your 400 so it depends if you want the loud sound but performance is great

 

i got it from dennis kirk. they appear to be a bit more expensive than some other sites but i have ordered twice from them and the parts arrived when they said they would. i called them once also and an actual person answered the phone, that doesn't happen alot.