Cardiff have scored 4 goals away from home, the 2nd lowest in the league. That was against Fulham (2), Hull (1) and Chelsea (1). They only won one of these games. In other words, they're not good away.
I think we can take them fairly wasily if we play like we have been. We haven't scored less than 3 goals at home since our lose to Southampton, and have scored no less than 4 in our last 4 home games.
If we're going by this, and how little they have scored, it shows that it should be a big win. But that's only logic, they could park the bus, which they're actually quite good at, but on our form, can't see it happening for them.