Think some folks here are getting off key. Whether dirt bikes or any OHV or other motorized vehicle, if your going to be motoring in areas with sound and/or spark arrester requirements, don’t test the letter of the law or gamble if a Law Enforcement Officer will or will not check you for compliance. It is part of their job BTW to do so, as necessary. Fires have ignited due to exhaust spark, though I didn’t believe it possible for years. If you want to run loud, non-spark arrested exhausts, ride in areas where it’s okay. Simple as that.
I grew up in So. Cal racing dirt bikes with open expansion chambers (2-stroke, no muffler and really loud for you younger folks) because that’s all we had and didn’t know different. Besides, that loud sound felt like huge power! LOL. That is, until Sierra Club and many other concerned folks began stepping in. They didn’t much care for what “WE“ liked doing. Granted, it wasn’t just the noise, but the impact on the lands. That was the beginning of “booby traps”, loss of lives, land closures nation wide and expensive court cases. We‘ve begun seeing this in BAJA too.
Today I recreate with family and lots of “old fart” friends. Some of us can still ride pretty darn fast, can’t hear too well, can’t see too well, but we all enjoy the scenery be it desert or mountain. We have a huge variety of UTV machines amongst us. We pickup trash someone else packed in but didn’t pack out. We respect others that we encounter, showing trail etiquette to all.
I suggest considering all facts and where you intend to ride before you make your machine much louder than intended. You’ll find many others don’t share your appreciation of ”but it sounds so much better”.