NEWS With two weeks to go in the regular season, races are tightening up and down the standings in both conferences. There are bubble teams trying to leapfrog lower-seeded clubs for a coveted spot in the postseason; and middle-of-the-playoff-pack clubs vying for the most promising seedings. Perhaps the most intriguing races, however, are atop the respective conferences. San Antonio’s torrid second half has the Spurs (40-14. .741) percentage points ahead of the Oklahoma City Thunder (41-15, .732) in the Western Conference,