Its quite a bit bassier/boomier than I expected at low RPMs as the deep sound doesn't translate well in the smartphone videos I had seen. But just as I wanted, it gives the car more sound at those low RPM, allowing a little more boxer sound and just a deeper noise. At higher RPM on full throttle (over 4000) the sound is overshadowed by the engine, which I like.
It also gives a nice sound on overrun when you change gear at high RPMs, and some way more satisfying blipping sounds and a few pops as well.
It's still bedding in though, as I've only managed a little more than 300 km since it got installed.
Nonetheless, here is a cold start of it, as well as some pictures.