I always thought that too (re: top speed restrictor), but what caused it from what I'm led to believe, was due to a public outcry bout the outrageous speeds these bikes were capable of straight off the showroom floor. Correct me if I'm wrong (which I'm sure somebody will), but suzuki was feeling the pressure and the Australian spec busa's speedo started reading 280 then dash which signified 300 but was not written on the speedo to appease the public.
Alot of the guys on here drag race and need the all the top speed they can get, and me personally I dont want my dinner to get cold.