All the research that I have done has shown me that the lx and ex do have different engine code numbers, other than that the only thing that I can see thatis different is the valve train. As far as engine block size they are both still the same 4 cyl. So in theory, I think that an ex part will fit an lx. As far as clearance for the header itself, I'm not really sure. Does this make sense to anybody else?

 

More than likley the EX part will fit. The intake and exhaust head ports are more than likley the same size. If you have any doubt, call a good shop in your area and tell them your thinking about buying headers but you just want to be sure they'll fit.