'97 (I think the first year they made B20's) or a '94+ B18B (LS) head may get you some extra performance, but very little (the port shape and what not may be better but I don't know specifcially).

Regardless, swapping head will not fix the OBD II problem. A majority of the sensors are located on the block and the biggest issue with an OBD II swap is the CFK (crank fluxation sensor) which is actually located on the oil pump). I know your trying to build it for cheap, but I"m telling you now, your just going to end up spending more money in the long run to either fix all the problems and headaches your going to have or to just redo it right the second time. Save up some money and just buy a '94+ LS swap.