The Honda S2000 can be purchased from the Torn Docks. It can also be obtained through the "Hijack a Car" Grand Theft Auto crime. It is obtained about 1% of the time (or roughly one time for every 100 successes) from "Hijack a Car." 
The Honda S2000 cannot be found through city finds but can be traded between players.
- Damaster, GTA Crime Stats (14/02/23)