First off those videos are N54 335i's. The N55 335i mufler delete sounds much better!
I have had a muffler delete on my N55 for about a year now. I can honestly say after a month I got used to the drone. I personally think it also sounds great. I never made a video of it, but there is this.
My car is at 2:04 the car after mine is an N54 with a muffler delete as well and you can tell the difference in sound quality.
It is loud, but that's what I wanted.