We're a little late reviewing Hori's official Mario Kart 7 Wheel peripheral, but I'm somewhat glad we are, thanks to some of the non-racing games I played with it on a whim. If this was just a piece of plastic meant for one game, the wheel is a $13 novelty at best, a luxury at worst, and not something where any recommendation really means much. Playing other games, however, shows the wheel has more value than that.
More than just licensed by Nintendo, the peripheral's packaging touts its compatibility with Mario Kart 7, and it does play well with the game's first-person driving mode. After fitting the 3DS into the base and starting a race, you press up on the device's D-pad and enter that perspective. The wheel is meant to assist the tilt-steering mode using the 3DS gyroscope. There's no obstruction to any port, to the stylus holster, cartridge slot or headphone jack, and you can hot swap the wheel on and off the 3DS if you feel like it.
Still, driving a few races without the wheel didn't impart upon me any real sense of necessity or performance advantage, although the larger bumper buttons made manual drift a little easier. While I've read that disabling 3D has been advised when using the wheel, because of the way it alters your point of view and distorts the screen, I didn't find this to be much more of an issue than playing the 3DS without the attachment. The wheel didn't force me to move the 3DS more than I usually do, and if first person driving isn't viable because of the distortion in the parallax barrier or whatever, that's not the wheel's fault.
It may be just me, but I found the solid base encouraging me to move both hands when I turned, keeping the screen's vanishing point mostly stable to my eyes. Without the wheel, I had a tendency to pivot one side up or down with my fingers and keep the other stable. That more often led to a screen position that distorted the 3D effect.
For Mario Kart 7, it should be noted that, while in first-person mode, you can still flick-steer with the analog-pad for minor course corrections. However, some powerups (specifically the Tanooki tail) are more difficult to use, if not useless altogether, because of the limited perspective. None of these limitations have anything to do with the wheel, but the mode itself.
It was in other games, particularly the just-released downloadable Zen Pinball 3D where I felt like this was a peripheral worth owning. Zen's biggest drawback on the 3DS is the size of the screen and the starkly downscaled size of the table you're playing on it. There's nothing that Hori's Wheel can do about that. But it did provide a very stable platform for my hands, whether sitting upright at a desk or reclining in a chair or couch, or sitting upright in bed, that helped me keep the 3D screen fixed in the "sweet spot" for viewing. Zen Pinball is also an example of a good game for this peripheral, because it's principally controlled with the left and right bumper buttons, which on the Wheel have large triggers situated at the index fingers of both hands.
On all titles, the Wheel provides the same kind of long-term comfort and stability. Its heft kept me from jostling the 3DS for minute controls, such as button strikes or hard presses on the joypad. I'm prone to making swoopy-hands gestures with my 3DS when I play it anywhere other than my desk. The Wheel more resembles a twin-analog controller than a wheel after you play it on some non-driving games for a while. This is probably deliberate.
It's not a small peripheral and won't fit in a carrying case unless that carrying case is also a bookbag. There are other attachments out there at budget price points that also seek to deliver the same thing. If you think of this more as an ergonomic grip for your 3DS, its value becomes a little more apparent.
While I would not call Hori's Mario Kart 7 Wheel indispensable or a must-have, it does provide a solid playing base for those using a 3DS for long bouts at home, for more than just the platform's signature driving title.
The Hori Nintendo 3DS Mario Kart 7 Racing Wheel is available now for $12.99