Im not hating the car tire (aka " The Darkside") thing. I only knowI wouldn't do it. I've ridden with a lot of the VTX guys that have done it. Works great for the highway . Twisty roads on the other hand if you don't know what you're doing it's only a matter of time you kill yourself. Of the 4 VTX guys I knew 2 have wrecked ( due to riding too hard with the car tire ) ,one went back to a motorcycle tire and the other doesn't ride anymore because well.... He watched 2 of his buds crash hard. I will mention that they all rode beyond the limits of most cruisers.
If I only did mostly highway riding I would actually consider it since you are not really ever requiring major leaning and even with a very sticky car tire you'd get 3-4x the mileage than a Metzler. At a 70 degree angle though your rear tire patch isn't much at all with a car tire.
But with that said Im still not hatin, . Looks cool. Just know your limits.