Ok, so I drove my E89 Z4 from the installer garage to my workplace and was feeling a bit underwhelmed because I didn't really notice a difference in sound.
Hooked up the wiring to the harness and played around with the remote valve controller, still not much excitement. Revved her a bit in the parking lot, not much different than than the usual burbles. Actually, the sound profile didn't sound much different than stock.
I even started asking myself if this is all that titanium exhausts have to offer. Sure the throttle response felt a lot more immediate and the car felt easier to turn, but the drama was missing.
Sport+ mode was engaged and all valves opened, but it only felt one notch different. Were my cats the problem, overly restrictive maybe?
For some reason when I went to go home for the day, everything changed. Then I pulled out of the lot and the true power and drama were on full display, and then some.
The idle tone changed, the roar at even 50% throttle changed. I was so scared of the sound that I don't think I even manged 100% throttle at any point today. I went from disappointed to muttering to myself "omg omg omg she's so F'ing loud..."
The ride home was way too short now that she has awoken. Perfect sound when I send her and perfect sound when idle now. I don't know what happened, maybe there really is a break-in period, or maybe the initial plug-in and playing with the remote at work didn't trigger her at the time, I don't know.
All I know is I love this exhaust system and appreciate my car even more because of it. It may not be Vanta Gold or even an M2/M3/M4, but the car sure does sound like it belongs. She absolutely screams now. Worth every penny.