Megu, perhaps in a bid to cultivate a younger crowd à la Matsuri/Hiro, is relaunching its upstairs lounge as “M by Megu.” Instead of Bianca Jagger riding in on a white horse, Tyson Beckford will roll into the launch party tomorrow on a motorcycle custom-built by Keino Sasaki (other Japanese artists whose work will now grace the refurbished space include CR and Kaoruko; the trademark tapestries will stay put). The main difference here is that the bar has been halved to make room for dancing from 6 p.m. to 2 a.m., and a booth will host D.J.’s picked by a former MTV Japan V.J., Mami Shirakawa. Slight change in the staff uniforms, too: The waitresses will be wearing — wait for it — designer swimsuits. Wait a minute, swimsuits? Isn’t Megu the restaurant that was hit with a sexual-harassment lawsuit? Eh, whatever, we’re assured they’re tasteful.