Can parts go on a Honda Civic EX from a Honda Civic SI?
I assume you are talking about a 1996-2000 Civic EX and a
1999-2000 Civic Si. If so then yes, people do it all the time and
practically every part will fit and work on your EX model,
especially if you have a 1999-2000 Civic EX. Interior/exterior
pieces, suspension, engine parts, etc. That's the great thing about
hondas.