Just got this mod done at Unlimited Performance too. Awesome 2 thumbs up!! Just perfect, it's not too loud. When you're on the throttle, shifting through the gears, it just sounds so much better than stock. More aggressive, throaty - hard to explain.
Also got my ZHP shift knob and black kidney grills from Calgary BMW, installed both myself, very easy thanks to the forum DIY threads.
The shift knob is great - more direct, heavier and shorter. Improves the driving experience.