The flex will only play a very small part in the distance and that only comes from increased loft and face closure on the softer flex. The longer shaft length should provide more distance assuming you are still making center face contact. Also the weight may feel quite different as the Pings are naturally lighter feeling in swing weight vs. Titleist and combine that with the fact that the Pings are 1 inch shorter than the Titleist so that the Titleist clubs might feel a bit heavy to start with. That will probably just be something that takes some getting used to though.
Only other consideration would be the lofts of the two which I am not sure about off the top of my head.