Run-D.M.C.’s Raising Hell remains the turning point at which hip-hop crashed through mainstream barriers and never left. Anchored by the crossover smash “Walk This Way,” the 1986 blockbuster still sounds like a revolution unfolding in real time. It has everything – hard-rock riffs, turntable scratching, itchy rhythms, hit singles – not the least of which are the trio’s invigorating raps and inseparable chemistry. And now it’s the first rap record afforded audiophile treatment, courtesy of Mobile Fidelity’s simply illin’ edition.