Well I just got the FMF Titanium - 4 Silencer on and took it out to test it out and I experienced none of the syptoms of richness or lean. It had perfect response and never stumbled anywhere, even with completely stock jetting. I was wondering if this could be a weird situation, where it works with stock jetting, or if something is up?

 

I have a WB slip on, on my 2002 BAJA. I feel it runs like a scalded cat, but.........everybody tells me it is probably running lean. Which, when you run lean you make good power. But it shortens engine life. So you may have a same situation as me or might be lucky have found a perfect match! Its hard to tell, until you run it awhile and check your plugs.

 

If the fuel and air mixture stays the same, that means the the air flow did not increase, which would mean there is no power increase, making the pipe only a cosmetic enhancement. However, the pipe you speak of does not have the noise baffling set-up of the stock pipe, so air flow most definitely changed. And since you have the Dynojet stage 3 kit, this means you're running a high flow filter like K&N or similiar directly on the carb, which makes for mega more air flow. All this air flow increase needs more fuel flow too, and the instructions in the Dynojet kit are pretty acurate for the most part. Run the main jet they recomend, or one richer if anything because I think they tend to lean a little on the lean side anyway.
02Baja is right - lean makes more power, but at a cost.