Ok I have a 91 prelude si with the B21A1 now I have already ran into trouble trying to distinguish the difference between my SI and the 2.0 SI and the 2dr Coupe SI (like at the insurance office and the bank) when we were trying to figure out which one it was. I know what kind of car and engine it is and all that stuff, but Is the 2.1 a rare engine or what? will I be able to find headers, etc... if not what kind of headers will I need to use?