This is from the website
http://www.bosozokustyle.com/content/what-bosozokuThe Bosozoku style is often referred to with a lot of different names:
Shakotan -- Shakotan literally means "low car" and is used mainly for indicating extremely lowered streetcars with wings and big exhausts tips. The manga/anime of Shakotan Boogie features two brothers driving extremely lowered cars. One of them being a white Toyota Soarer Z10, hence the popularity of that particular car under Shakotan fans. This style is the mild variant of the Bosozoku style.
Yanky style -- during the 70s and 80s in Osaka area the street fashion became to wear colourful Aloha shirts and pants and this caused the wearers being called Yankees. Most of the "bad boys" were wearing the Aloha fashion and hence the Bosozoku became equivalent to Yankee style. The writing of this style is officially with double ii, so Yankii.
Also one of the cars in Shakotan Boogie was a blue (later on painted yellow) Nissan 240 S30Z with widened fenders and "Yanky Mate!", probably same as the Yankii fashion, in big white letters on the hood. People who copied this styling started called it Yanky style. Basically it is the same style as Shakotan with the exception of the wide fenders but mostly people call the moderate styled cars Yanky style.
VIP style -- VIP style is more or less a crossover between Shakotan and gang cars: extremely lowered luxury vehicles (lots of bling!) are filled up with as much novelties as possible and ride on big rims. Sometimes very close to Bosozoku style, however the Bosozoku style is more or less the low budget version of VIP style. Also VIP style tends to use only newer cars while the Bosozoku style uses the older cars from the 70s till early 90s.
Kyusha style -- Kyusha style literally means "Japanese old classic car" which in a lot of cases mean it is an old car modified with some (smaller) fender flares, lowered and nice rims under it. So it should not be the same as Bosozoku style.
Grachan -- Grachan or Garuchan comes from the 70s and 80s Grand Championships on Fuji Speedway. The Bosozoku used to have big meetings on the parkinglots of these events, hence the name. These cars should also match the same bodyshape styling as the cars running on the circuits, with big wide fenders like used on the Super Silhouette styling. So this style should be part of the Bosozoku Style.
Bosozoku Style -- the Bosozoku style distinguishes from all the styles above; the wild styling of the cars combining all styles above! So it lowers the cars extremely like the Shakotan, it uses big fender flares from the Yanky style and resembles wild bodyshapes from the Granchan style and adds the wicked exhaust styling from the motorcyles!
