This year, the WBCN Rock ’n’ Roll Rumble, which moved from the Paradise to the Middle East back in the ’90s, waited until the final to move from the upstairs where the preliminaries were held to the larger downstairs room. And all three of the bands chosen to compete last Friday night — the two semifinalists plus a “wild-card” — seemed liberated by the possibilities of the scaled-up stage, the larger sound-system, and a good-naturedly rowdy capacity crowd. None more so than wild-card picks the Campaign for Real Time (C4RT), a bold six-member, multi-racial explosion of fusionaries who exploded when they hit that stage with their mix of hip-pop dynamics, multi-vocalist MC rapping, hard-rock guitarisms, and pounding drums of the real and programmed sort. Yeah, C4RT are flirting with a dated formula. But they bring a quirky freshness and enthusiasm to what they themselves have referred to as a Timbaland-meets-Talking-Heads sensibility, momentarily erasing bad memories of Limp Bizkit in favor of the recent triumphs of Black Eyed Peas.