What CN90 said.
Do the same thing as previous, BUT: take some paper towel and affix it as best as you can at the bottom of the oil filter housing - if it leaks it will soak up all the oil. If the leak is big, it will drip down.
The way the OFH is placed together with the air straem created by the fan will make the oil drip/channel where you see it.
When you crawl underneath the car - you wil see the subframe crossing right under the oil pan - it's a bear of a job for the i6.
I changed the oil pan this weekend on one of my friends X5 - it's a v8 and a very easy job.