i`ve heard both eisenmann and meisterschaft sus in person. The meisterschaft is louder because the back exhaust is made out of two little exhaust, while the eisenmann back exhaust is made from one piece. I don`t have videos to prove this to you

edit: video found on youtube
YouTube - Meisterschaft GT Exhaust Installed on BMW E70 X5 4.8i V8 (Stock vs. MGT)