Haven't played any of them (except an Excite Truck demo...pretty cool), but to answer one unanswered question (unless I missed it) - you asked if the steering wheel will work with all racing games.

Last I heard it was just going to be a "cover" (for lack of a better word) that your Wiimote was put into sideways that looked like a steering wheel so it felt more natural. Does that make sense? It doesn't add any real functionality (which is why it's free), but it's like those tennis rackets and golf clubs and swords that you can put the Wiimote in....mainly to look / feel cool and life-like.

So, unless they've changed it, yes - it should work with all racing games where the Wiimote is held in a sideways position (AFAIK, all of them)