i need a pipe thats somewhat quiet yet gives lots of power for the 400ex.

 

Not sure which ones are quiet however I can say from experience to stay away from DG because they are really loud.

 

My buddy has a super trapp on his 440ex sounds great and not to loud makes pretty good power too.

Also look at the new white bros E2 quiet with the end cap installed and you can remove it for even more performance but the sound level goes up.

 

i think the fmf powercore and the white bros e2 are both quieter pips

 

my eseries is pretty quiet,it is quieter than my old supertrapp was.

 

FmF Powercore is loud 100dB to be exact i think