Snow Crash has been hailed as being a visionary work on the fractioning of American Society, as well as fortelling the social impact of the internet and world wide web. One thing that Neal Stephenson didn't seem to be able to predict fully was the future of rap music, and Sushi K, the Japanese rapper who has a passing role in Snow Crash is a sign of that.
The idea of a Japanese rapper in 1992 (or during the proceeding years, when the book was being written), was indeed innovative, and foresaw not only the spread of hip-hop culture in East Asia, but also the Asian motif adopted by rappers such as The Wu-Tang Clan and Del the Funky Homosapien. However, from the actual rhyme used by Sushi K, we can see that Stephenson either doesn't know much about rap and its future developments, or else he is just a very skillful satirist.
The one rhyme of Sushi K's that we know of is set to a sing-song, AA BB CC rhyme style, with the exception of two lines that are AB AB. Although the vocabulary and bragging style are actually fairly sophisticated, and fairly in line with what rappers did both at the time of the books writing and the time of its setting (around the first part of this decade), nothing else in the rap is sophisticated or up to date at all. The rhyme, after all, begins with "I'm Sushi K and I'm here to say...", a hip-hop beginning so cliched it probably hasn't been used seriously on wax since 1985.
Of course, Snow Crash is not particularly a book about hip-hop. Stephenson could have included Sushi K merely as an interesting diversion (in 1992, no one knew whether hip-hop would be around in another ten years), or given the fact that Stephenson is a satirist, he could be mocking either the overly enthusiastic adoption of rap by Japanese culture, or he could be satirizing rap in general.