Unless you've spent time in Japan you have no idea what the Bosozoku are really like. There custom car and bike culture is just half of it. They are legit gangs there and some with ties to the Yakuza. They like to disturb the peace more than create violence. There biggest claim to fame is how they would do these midnight runs usually on a week night causing outrageous traffic jams.
One gang or several will drive and ride on major roads and highways going as slow as possible all the while revving their uncorked overly built pipe organ like exhaust systemed vehicles to the rev limiters. When you have a 12 to 20 vehicles going like 5 mph revving engines till they scream on a major urban/suburban roadway the sounds are unforgettable. Many times they rev the engines in almost rhythmic fashion. I've been awaken many a time when they drove past the base I was stationed at.
The Japanese police would try to chase them down and stop them but usually failed since they were always outnumbered. The police resorted to paintballs and paint grenades filled with unwashable dye to mark the offenders.
The worse time of the year is on New Years Eve when all the Bosozoku gangs are out in full force on the major expressways in and around Tokyo. They literally park themselves on the highway and create a blockade to prevent people from driving through and cause massive traffic tie ups. I on a few occasions would drive down the shoulder, where for some reason they would not block off with vehicles but the gang members would hang out on. The times I did this I usually got through and many times with them waving and yelling hello to me. But I think it's because they saw I was an American and also my license plate had the letter E on it to show it was a American military personnel owned vehicle. But as soon as one Japanese National would try and do what I was doing they got blocked in.