Well those are Chassis codes and the ones I know for 96-00 hatches are:
EJ6 - North American CX/DX Hatch (I think there's a Euro EJ6 too)
EJ9 - European 1.4 Hatch
EK4 - JDM SiR or Euro VTi
EK9 - JDM Type-R
and just for the heck of it
EJ6 is also DX Coupes and DX/LX Sedan's
EJ7 - HX Coupe
EJ8 - USDM EX Coupe/Sedan, CDM Si
EM1 - USDM Si, CDM SiR, Euro VTi Coupe
EK3 - JDM Ferio Vi/VTi
EK4 - JDM Ferio SiR (I think)
And those are all I know, I'm sure there's more.
actually the EK3's had 3 stage VTEC D15B's I think.