I would bet that from the factory these 4.4's come in a lil piggy(rich) and increasing the airflow will lean it out somewhat, but I still doubt that the pcm could not handle. Now if your totally took off the filter you might have been stuck in a lean postion. In my C5 Corvette I had to richen up when I used a Halltech TRAP intake. But the C5 OEM intake is very restrictive and the Halltech opens up a floodgate of air.
To take advantage of all the mods it is always best to dyno tune your pcm. However, I do not know of any software for the x5 that allows you to do that. Something ls1edit or hptuner would begreat for the x5.