The FMF "Q" is pretty quiet, quieter than a stock YZ, much quieter than an uncorked WR, and world's quieter than the typical aftermarket pipe. I'll assume you are referring to this FMF model. The "quiet core," or whatever that thing is called, is IMO still louder than stock YZ, which I believe is said to be around 99 db. I never put my FMF Q on a meter, but I parked my Q-equipped YZ next to a stock 520EXC and it was just as quiet at idle but a bit louder under a load, especially as the revs climed. I would think that whether or not the Q is below 94 db would depend entirely on the nature of the test (distance of the meter and rpms of the motor). As popular as the YZ/WR is I would think you could call the organizers and ask what pipe will allow your bike to pass. Finally, please don't take my opinion as any sort of endorsement on my part of the FMF Q pipe, which is IMO the biggest pile of overpriced, overhyped junk I have ever attempted to put on my bike. I think it represents a bad design put to shoddy manufacture and sold via questionable performance claims (it kills the top end, but claims to add 1 hp). That wouldn't be so bad, happens all the time, but in my case the damn thing fell apart. I didn't believe the power increase hype, I just wanted a quiet pipe, and it was, but it is poorly thought out and its length and weight are not sturdily supported, and it fell apart after about 20 hours of use. Hope this helps.