so, you don't have to take off the crosspipe and you probably don't have to replace the cooler.
In my case, the leak was coming from the gasket where the cooler meets with the engine. Just make sure you clean really good around the area before you take it off. It's also a great time to put in a new thermostat, since you have to drain the coolant.
pretty good writeup here: http://www.subaruoutback.org/forums/...lter-leak.html