Just picked up my new 400ex Monday (yellow). I want to put on an aftermatket muffler. I would like some input as to what others use and have had success with. Currently I am between a White Bros E series, Pro Circuit T-4, or possibly a Graydon. Any help would be appreciated. I am not going to race, I just want more low end torque. Sound really is not an issue either.

 

out of the ones you listed id go with the procircuit.....but i like yosh full system the best....

 

Congrats on the new purchase. out of the ones listed I too would go with the T-4. I myself just purchased the full LRD exahust and love it! My own personal opinion is that the ones that you have listed are just your typical go down to the motostore and buy one type of exahausts. Do a littel bit more shopping, there are alot of pipes out there, DMC,YOSHI,SPARKS,LRD,CT,GT THUNDER these are the more elite companies that have been in this industry the longest. Pro Circuit and FMF have just recently been developing 4-Stroke exahusts, I personally would give them a little bit more time to develop their pipes. just my 2 cents-

 

Any slip on muffler that you mentioned will work good, except for the FMF, I have broken 2.