It's hard to spell!- Bo so zo ku
Japanese motorcycle gangs, originally. They imitate and many times exaggerate Super Silhouette racing and other 70's and 80's phenomena through bike and car modification. There's a certain charm to some of their cartoony custom creations. If you google it (bosozoku or zokusha are the same thing) and can't stand it, try shakotan ("low down") or kyusha (Japanese classic car) and work your way up.
Here's a nice mild boso example from back in the day. Nowadays people mostly do this style because they dig it, not because of any gang affiliation.
And a beautiful shakotan ("low down") Kenmeri Skyline. This style of wide wheels, stretched tires and low suspension evolved into the "stance movement" of today.
See? Not so bad.
Also remember the cars they're imitating weren't subtle in the least, and coincidentally, were mostly dictated by aerodynamics! (Don't you love when things go full circle?)