There are a few differences between the JDM Type S and the USDM Type SH. I might be wrong about some of these, but I'll list what I think is different:

The intake design is a little different, I think the throttle body is different, as are the pistons and camshafts. I think there are some other internal differences, but I dont remember what they might be. The valve cover is red. And then there are the Type-S badges. Also, I think those JDM foglights are standard on the Type S, but I'm not postive about that. The Type S should also have a different front lip than the US model.

Its possible to upgrade your car to the Type S. You can do an engine swap, or I assume you can just switch out all the parts for Type S parts. But it seems like that would be a fairly involved process, not that replacing the engine is any easier. And I dont think itsworth it considering how much money and work you'll put into this for a 20hp increase.