2003 CRVII with k20A4 engine

[Hondak20A]

Hi, My car is 2003 CRV II with k20A4 engine, could anybody tell me what
the difference between k20a2,a3,a4; could a4 be modified more better?

[DaX]

I'm not sure exactly what the differences are, but the A2, A3, and A4 part of the engine code designate the head type. There are probably small [or not so small] differences in the heads.