March 27 (Reuters) - The mainstream quotation range for xylene in the South China market is 8,400-8,550 yuan/ton, unchanged from the previous trading day. Sinopec South China Company's ex-factory price for toluene is set at 8,500 yuan/ton. Crude oil closed sharply higher overnight, and the aromatics night session also strengthened, providing support for toluene and xylene. Domestic spot supply remains tight, and traders maintain a strong price-supporting sentiment. The spot market is expected to show a stable to firm trend today.