At this writing, the Spurs are the best team in the West. All of the numbers since the beginning of March suggest as much. The Nets loss was due to Ginobili not playing, the Suns loss was due to fatigue and the Grizzlies loss was due to poor coaching. None of these three things will be the case in the playoffs (right now, Ginobili is healthy and the type of poor coaching I'm referring to is over managing minutes and playing all twelve guys, which barring a blowout isn't happening). The last time they were cleanly beaten was the Lakers game.
The Spurs are not in the Lakers bracket, which means that they won't face each other until the conference finals, should they both make it that far. Let's face it, they are the worst match-up for the Spurs, so with them out of the picture at least until then (I wouldn't be shocked if they're eliminated in the second round, depending on who they face), the Spurs are eminently capable of reaching at least the conference finals.
If anyone's been paying attention, that shouldn't come as much of a surprise. A slight one, because they'd be without home court for both rounds, but they're really not your typical six-seven seed. Not even close. They were expected to be better than the teams 2-6 and because it took a while for that to come to fruition, it doesn't bear itself out in the standings, but the Spurs are the best of that bunch (at least right now).