The Twin Cities rock radio dial is shuffling again. In a week or so, X-105 will switch to something between the current hard rock format and the old alternative rock format of the former Rev-105. Meanwhile, 93-7 The Edge will get harder-edged, perhaps in a bid to compete with Rock-100, which starts with Howard Stern in the morning and plays hard rock the rest of the day. The Edge and 105 are owned by Cap Cities ABC, which also owns the giant KQRS. Chancellor Broadcasting recently bought Rock-100, which used to be BOB, the country station. Chancellor owns six other stations in the market. Robert Unmacht, editor of the M-Street Journal, a weekly broadcast trade newsletter, says while the reshuffling is possible because of the radio aglomeration in the Twin Cities, what's happening is the legacy of old FCC actions conflicting with the market's growth.