The new FB engines are the first major top to bottom engine design done by subaru since like the mid 90's. These new engines no doubt are designed with the intention to work with DI tech in the future - no the 2.5 is not going anyplace. If anything the 2.5 FB with various new tech added to it may replace the old 3.6 if the fuel cost and EPA fuel games push Subaru hard enough they need to find added fleet mileage by dumping the older 3.6