06 400ex

[ex_rider911]

i need a full pipe pafurabley under 500$

[WhtPrd09]

HMF all the way!!!

[hornetgod13]

The majority of the folks on here will recommend HMF. I have a HMF slip on coming for Christmas. Thanks Santa!
There are tons of threads with this very same question on the website. If you use the search feature you'll find hours of reading on the subject.

[81 clark racing]

HMF OR CURTIS SPARKS. HOWEVER I HAVE A PROCIRCUIT T4 AND I LOVE IT !!

[blasterandy]

Go for a highly modified get a sparks for a light to stock get an HMF even a highly modified will work well with an HMF. Sparks Just seems to be better a putting out ponies on the more built motors. Yea you will find hours of reading on this if you search there are sound clips of both.
Now let me be the dictionary this is how you spell Preferably. Don't worry I wouldn't have know if that was right or not if i hadn't checked google.:D Yea i'm a loser i know.
Welcome to the forum.

[procircuit406ex]

HMF, Sparks, Procircuit, Duncan just to name a few.

[vinson2000]

hey, just installed a two brothers pipe on my 400ex AWESOME . the installation was about 1.5 hours for the pipe and jetting which i done myself.the co. sent me the exact jet and everything. the 400 was fun before now its a very fast blast.now i have to do my wifes she even loves the extra power and sound.i reccomend this set up.to anyone.the part no. is 005_11010406 it includes tools and parts and hardware and also the jet you will need jetting was easy.