They're both very good lines, just for different people.  The Infernos seem to be better in the hands of a person with more revs, because they're very even arcing and smooth off the dry.  Excellent control balls, just unreal stuff.  The Zones are a lot sharper, more aggressive on the backends.  They work great for just about everybody.  BVPs will own just about any house shot you want to throw at them.  They're just older technology . . that's all.  PK18 is earlier and sharper, BVPs on a house shot seem to be directly between the Infernos and Zones for look on the lanes.  The cores keep the BVPs a little smoother, but the covers make up for it.  Different price points, but I wouldn't say they're different performance points.  Depends on what look you're going for, the only difference lies in the age of the technology.
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Overdose, lethal metal level in my blood, it freely flows, embrace the pain, crush the suffering and cleanse it with the river surging through your veins.