KDXRIDER.NET

I've got a 2001 KDX200 that came with an FMF Gnarly pipe that I've had on the bike since I bought it.
But, the original owner gave me the stock pipe, too.

I'm trying to go through the jetting process and have struggled with it a bit.
I'm wondering if there's any advantage to switching back to the stock pipe (whether for jetting purposes or just in general)

I ride mainly trails and I'm not a very fast rider.

What are the pros and cons of the stock pipe vs FMF Gnarly pipe?

The pros of the gnarly pipe is it helps to bump up the bottom end a bit on the 200 while leaving the top end alone. Jetting it isn't any different or more difficult than jetting the stock pipe. And it's also lighter than the stocker. The con is it's more expensive, but you already have it so that's a non-issue.
If you are having issues jetting, the pipe is the least likely component. Make sure that all your soft parts (air filter boot, reed boot, air filter) are good and no air leaks. Also make sure your top and bottom end are in good shape. And of course the most important make sure your carb is truly cleaned and serviceable.

Thank you Bufftester.

Stock is quieter, a little less power, heavier

I've wondered this question too, when I was younger I had a wr200. It had an aftermarket pipe on it and came with the stock pipe, I rode it for a while with the aftermarket pipe then tried the stock pipe, the stock pipe was so smooth and tractable in comparison, as you get older you realise power is not as important as we were led to believe, my suggestion is try it, this kind of topic is similar topic to the snorkel removal, 80 percent of people will tell you to remove the snorkel, I put mine back in and loved it, personal preference

I've been riding mine recently (stock pipe/older style FMF silencer) with the snorkel in. Then we did a big day riding Sunday and half way through I pulled the snorkel just to see how much I'd notice it. I think it does give it a raspier growl, maybe improves throttle response a bit. Definitely will keep the snorkel around though for when I'm in the mood for less noise.