I have a Riss Racing Exhaust that isn't a Muffler Delete but is pretty loud with no drone. (At least in my experience)
Fitment is good and has already been fixed by professional exhaust shop. (I had this exhaust sitting in my garage over a year now.
I'll sell it for $350+ Shipping (OBO).
It's a full 3" catback exhaust.
I think I have a video of it with some minor revs when I had my 135i. (I will post when I find it)