Ratings get squished a bit towards 1500 (at 2521 you're considered about 2200-2300). This squish is exponential so there is no "hard" limit on the difference but would take really high absolute values to produce high differences.
Ratings shown can be less than the raw value due to variance, as you wait in the queue the raw value starts being considered (so the 1352 dude could've been a, say, 1700 who hadn't played for a long time and thus had high variance).
After those effects are applied there's a limit (I don't have access to its value at the moment).