whats up man, welcome to hondclub
Your car is either an LX or DX. I dont think they made a 4 door EX. I would suggest looking at the title for your vehicle. I know mine says on there. Do you still have the body emblems on the car? The model letters are on the passenger side of the trunk lid. There is some way to tell by the VIN number but you probably could call a honda dealership for that.
As for modifying your car, it all depends on what you want to do. They make so many parts for civics, especially that year, so if you look on Ebay, you can probably find anything youll want