THIS SYSTEM IS INTENDED FOR RACING PURPOSES ONLY.
What does this mean? Am I gonna have cops all over me? Is it street illegal? Will it drive me crazy from the noise? Will it give me 20hp?
In order for manufacturers to sell pipes that don't meet noise reduction requirements, they must label them for off road purposes. This way, they can't be held legally responsible for any tickets you get from local ordinances prohibiting loud motor traffic and move that responsibility to you. They are technically NOT street legal, but routine enforcement is rare.
Cops can find something to ticket you for whenever they feel like it. Loud pipes will only draw their attention to you. But, they are more likely to ticket you for speeding than for loud pipes. However, if you curse and disrespect them, they have lots of ticket pads they can fill out and have you sign.
Will it drive you crazy? Well, when was the last time you were evaluated? Might be interesting to see a before and after comparison.
Seriously, noise is fatiguing. If all your trips are short, there shouldn't be much of an issue. Long trips are another matter. It is a proved fact that long durations of exposure to noise ARE fatiguing and debilitating to the operator. If you enjoy operating your machines while you're less than 100% alert and reactive, then you're in for increased enjoyment. Otherwise get some noise cancelling earpieces to enjoy long trips. Unfortunately, simple earplugs also mask awareness of road events that you should observe.
It will NOT give you 20HP. If you get gains, it will be at High RPM near WOT. Low and midrange torque will likely be reduced, even if you re-jet the carbs properly.
You've heard the chorus from the pro-noise people. Now a short note from the other side...
Loud pipes are for Bozos with an inferiority complex who need the noise to gain attention for themselves from people who otherwise wouldn't notice their existence. Such people have been or are now so starved for attention, that anything, including being cursed at is perceived as a positive interactive experience.
The "saved lives" bleating has no basis in fact and is simply a manufactured excuse to justify annoying other people. It is a lazy, effortless way to appear to do a lot without even really thinking about others needs or desires and offers malicious contempt towards their comfort and denies any tranquility and peace they seek to exist within. It is equivalent of a smoker who purposefully exhales smoke into the face of non-smokers. Personally, I think loud pipes should be allowed only if they exit the bike in the face shield area of the rider where they can garner maximum benefit.
But, I don't have a really strong opinion on this matter.
Cheers,