FMF or Pro-Circuit ?

I like the Gnarly. I'm like, going to get all scientific on it. You remember Gordon Jennings, he wrote a book called "The Two Stroke Tuner's handbook". I have mine open right now to page 52, where it begins to explain the function of the pipe header, the transition, and all the rest of the exhaust pipe. It's considered "The Holy Bible" over at FMF and Pro-Circuit.

You can see it online at edj.net/2stroke/jennings/2stroketunershandbook.pdf

I'll attach an image of the pipe formula.  I'm still smart enough to buy a Gnarly, instead of making my own pipes.
 

Here is what the exhaust pipe looks like on Sam's "almost trials bike tractor feeling" KTM 250 Freeride 
Compared to my KTM-250 XC-W's  Gnarly

Here is the formula