MANILA Two parties have expressed interest in the price challenge on the management, operation and maintenance of the 94-kilometer Subic-Clark-Tarlac Expressway being conducted by the Bases Conversion and Development Authority . San Miguel Corporation and the law firm of Aguirre Abao Pamfilo Paras Pineda and Agustin, representing an undisclosed client, bought bidding documents and attended the pre-selection conference conducted by the BCDA on Tuesday.