A rapper was shot multiple times and killed and his passenger was critically wounded as he drove a Porsche down a Queens boulevard early Sunday, a police source said. Lionel Pickens, who goes by the stage name Chinx, was shot several times in the body and his 27-year-old passenger was hit twice in the back about 4 a.m. as they traveled on Queens Blvd. at 84th Dr. in Briarwood, cops said.