Cliff Lee vs the Sox: 4.06 ERA, 1.32 WHIP, .732 OPS against.
However, these are career numbers, and he's really owned the Sox since his breakthrough season. With the lineup being so left-handed now, he'd probably own the Sox even more. Adrian Gonzales doesn't seem to care though, hitting .700 (7 for 10) with three doubles and a HR vs Lee.
Roy Halladay vs the Sox: 4.39 ERA, 1.28 WHIP, .718 OPS against.
The Sox have always hit Halladay relatively well, but we all know what the dude is capable of.
All in all, not a pair i'd be happy to compete against, but i'm pretty sure Lester (who's in their "Ace level" right now) and a healthy Beckett, Bucholz or Lackey could rise up to the occasion and give these guys a run for their money.