from what iv'e read here in the past boost bottles and nos are a joke. expansion chamber is where it's at.
as far as sprockets people say 32 tooth is too hard to pull for most chinese motors, and 40 feels better then 36 overall.
King Sales and Service
these guys make all sorts of sprockets, and then depending what type of hub you're using manic mechanic makes a handful of adapters+sprockets designed for specific hubs.