I'm a PS4 person, but I don't think Infamous SS will outsell Titanfall.
Titanfall has some COD hype, and it's a 1st person shooter. Judging the sales of Infamous 1 and 2, I don't think Infamous SS will sell more than 4 million, unless Infamous SS is one of the best games EVER made (metacritic score 94 and above). I could see Titanfall getting close to 5 million lifetime, depending on how Xbox1 sells.
As for those predicting Titanfall selling 8+ million on Xbox1, the Xbox1 console may not have sold 13 million by the end of 2014. Currently, Xbox1 will probably sell 300-400k monthly (about 70-80k weekly) with a slight increase for a week or 2 around Titanfall release, and big increase around Nov-Dec.