This pic shows how they fit better than the ones at nike.com:
They are the most tappered pants I have. The top block (waist/ass) is big and roomy, you won't have problems with an M. The thighs get tighter and under the knee it gets really tappered, almost like thick leggings.
If you want them as in this pictures you should probably get an M:
On the european sites you can see the blue one off the model. Notice how tappered they are:
Edited by deadsunrise - 9/13/13 at 4:28am