Even my older one had a decent trigger, I wouldn't bother with a trigger upgrade, they aren't the most accurate rifle out there, you'd be better off buying better glass or just more ammo.
Sometimes you don't need to "upgrade" stuff and in the case of the XCR there really isn't much you can or need to do. If you really want to upgrade it have a quality barrel built for it. Other than that you're more just changing things than actually upgrading.
Just my opinion but I really don't see much gain from dropping a bunch of money on stuff for the XCR. It is what it is and if it's not what you want you'd be better off selling it and buying something else than trying to modify it to make it something it's not.