From the menacing, brushed-nickel skulls on its prow and tank, to the smoky graphics swirling around its sharknose fairing, Harley-Davidson’s 2012 FLTRXSE CVO Road Glide Custom means business. Even the names of its high-end accessories—Agitator wheels, Rumble Collection components and Heavy Breather air cleaner—are street tough. And Mr. CVO’s Screamin’ Eagle Twin Cam 110 V-twin is the Godfather of the family, for its time it was the most powerful production engine available from the Motor Company. Its arm-straightening torque will make you an offer you just can’t refuse.