But this custom Slingshot is cool as ... fourth wheel thanks to a four-wheel conversion kit, and a revised engine. What sort of revisions you ask? Two big ones, including a big turbo and swapping ...

And now they've got a new challenger on their hands in the form of the Slingshot. The 2.4-liter GM ... reinforced drive belt to the solitary rear wheels. In true motorbike-manufacturer style ...