Though you currently can't buy Mario Kart Wii without the bundled Wii Wheel (at no extra cost), you can buy another Wii Wheel separately. But if you're thinking about picking up a second Wii Wheel for anticipated two-player shenanigans after you buy the actual game, don't. It's simply not that big a deal; it's the proverbial gum in the bubblegum cards, which you buy for the cards, not the gum.
Plainly, the Wii Wheel gracefully clutches the Wii Remote, which snuggles in across the full Wheel span horizontally. Meanwhile, a button extender on the back gives ergonomic access to the otherwise-recessed B-trigger, and there's a little hole on the left side to accommodate the Remote's forward pointing IR beam, which means you hold the whole thing like a saucer full of marbles when you need to actually point at menus and such.
However, though a Wii Wheel rig clearly looks like a steering wheel, or is instantly recognizable as a cheap plastic replication of such, it doesn't actually behave like one, not acceptably anyway. Here's the thing: When using the Wii Wheel, Mario Kart Wii (and who knows what other forthcoming games) requires use of both thumbs, one on or ready at the left d-pad (for weapon launches), the other on the 2 button for gas (1 and 2 for drifts), so you're actually holding the thing face back and with a clawed rigor mortis grip, hands pretty much glued to the "9 and 3" position, thumbs ever-cocked. Real steering wheels or even most other steering wheel game controllers allow you to keep your thumbs relaxed, pointing naturally upward or inward or slightly wrapped around, often with button controls placed ergonomically nearby. But no such naturalistic tendencies are allowed nor even available with the Wii Wheel.
