you will have to use the 4v heads. and with the money you are gonna spend on the 4v conversion you might as well just buy a s/c kit made specifically for your car. cause youre gonna need to upgrade your fuel system, MAF, injectors, ecu, and probably some other stuff that im forgetting.
if you really want to do a 4v conversion, youre better off getting a whole 4v aluminum engine. A couple of reasons are: (1) The 4V block is aluminum=lighter. (2) The crank is forged steel instead of cast and held in place by 6 bolt maincaps in place of 4 bolt for the iron block. It also has a stock windage tray underneath. (3) A complete engine should come with many of the accessories that you would need, which would include front timing cover, chains, tensioners, shorter alternator, cooling lines, ignition wires, fuel rails etc.. Not to mention the big peices such as the heads, cams, intake manifold. None of which are interchangeable with the 2V parts.