I was wondering what do you think the best slip on pipe is for the 400ex? I was leaning towards the E-series and a k&N power kit . Thanks

 

check out www.exriders.com Do a search on pipes, and you'll hear alot of good stuff about the E-series, pro circuit, and yoshimura pipes. My preferred set-up is in my signature below.

 

Duncan FatBoy4!!! Without a doubt the best!!!

 

I know its a different motor but I have a Pro Cuircut T-4 pipe&silencer on my raptor.I will have to say that I love it.The results should be roughly the same on a 400ex.The sound is good and the performance gain was very good,also the price was in the lower end of the pipes I was compairing.Very easy to install,best bang for the buck,just my two cents.Good luck Steve

 

save your money and make sure you buy the oversize header pipe combo.Like the one that Curtis Sparks Makes or like the one we have from LRD's.
THATS THE TICKET......................

 

I have the Supertrapp IDS2 slip-on on my wifes 400ex. Nice power gains and sound.

 

I PERSONALLY LIKE THE DMC ALIEN DUAL EXHAUST.