It is possible, however, when you go into the project remember you are working with a fabric and not a metal, so keep that in mind as you drill. So, you don't want to make giant holes, keep them small.
One thing, you don't have to add a lot of porting to make a difference, I own a CP which has very little porting and it reduces the sound enough to prove how little porting you need. The CCI phantom barrel has even less, most of the noise comes from the gun cycling.
Also, keep in mind that the ego is going to be a lot louder than the demon no matter what you do since most of the noise comes from around the bolt.