Mary Beth Peil and Michael Laurence will topline Primary Stages’ Off Broadway production of “The Morini Strad.”Peil (“The Good Wife”) plays an aging violinist who wants to restore and sell her Stradivarius violin, while Laurence, the scribe-performer best known for the successful Beckett redux “Krapp, 39,” appears as the violin maker she hires. Based on a true story, play by Willy Holzman centers on the pair’s path to an unlikely friendship. Violinist Hanah Stuart, a recent Juilliard grad, will be on hand to provide live music for the two-hander. Primary Stages is coming off strong reviews for its current offering, Kate Fodor’s comedy “Rx,” which finishes up its run March 3. “Morini Strad” begins previews March 20 prior to an April 3 opening.