3 weeks later...
I can report that my Berk Street sounds even better now after 3 weeks! This thing sounds great, and puts a smile on my face very time I blip for downshifts!
No drone - and IMHO, I'm glad that I went with the street version.
2010 E82 6MT-M Package//PTF Dyno Tune//Alpine Weiss//Carbon Roof//Carbon R Spoiler//Euro Light Switch//Black Grills//Michelin PSS 235 255//Berk Cat Back//DTEC//ER CP Tial BoV//CDV Delete//Hardwire V1//