I had a 93 Supra with a T81 with 4" HKS Fireball.... I know all about loud lol.
But this, is a different type of loud, especially here in Germany, but if you know that's what you want, good luck man. People sell those Berk Races all the time, you could actually probly post the BMW exhuast as a potential trade +cash. Might work out for ya.
2011 BMW 135i - COBB V2 AP / VMR 710's / 4" AR Catless DP / BMS Intake w/ Air Scoops / Eibach Pro Kit / MadDad Street Series Axle Back / ER Charge Pipe / BMS OCC / Vorshlag Camber Plates / Sammich Sticker