Here is some product info for ya!

[Mobile Dyno]

Check out some pipe info in the dyno section. I posted results of HMF Slip-on and White bros. E-Series pipe. Check it out. It should answer some questions

05' 400ex All Stock vs E-Series (http://www.exriders.com/vbb/showthread.php?s=&threadid=246517)
02' 400ex All Stock vs HMF Slip-on (http://www.exriders.com/vbb/showthread.php?s=&threadid=246519)

[krt400ex]

wow u'd think that u'd get more power than that out of a pipe. huh, can u do a test of a yosh or sparks full system??

[GPracer2500]

Great info. Thanks for taking the time to share it with us!