Shitake mushrooms?

I'm having people for dinner tomorrow night and I'm making a pork stew. It has pork, tomato sauce, carrots, onion, red wine, thyme, oregano, basil, raisins, cinnamon, and mushrooms. I've made this recipe before and its one of my favorites, but I wanted to do something a little different with it this time, so I bought some shitake mushrooms. I was chopping them up earlier and tried one. They have a pretty strong flavor. Does anyone know if their flavor mellows or intensifies when they are cooked? Given what I'm making, are shitakes a good choice or should I go back to the store and get some portabellas? Thanks in advance!