Product quality brilliant, so easy to fit, took me less than 5 minutes. If I'm honest though, on my particular car and after import duty it didn't make enough difference to my car for the price.

Easy install. Does exactly what it advertised. Simple way to get a bit more rumble from your existing system. Should be mandatory.

Amazing product and easy to install and love that I can keep it in comfort mode but open the valves up to hear to cracking and popping lol

Based on the fact my X1 M35i only has a 4 cylinder B48 (which is quiet from factory anyway) I wasn’t expecting much. Controller install was very easy and valve connectors were accessible through the wheel wells. A total of 5 minutes to do both sides. Sound wise there is most definitely a difference. Tone is deeper and maybe a a little louder. In Sport mode you can hear the difference at idle when enabling/disabling, but in Personal or Eco not so much. However, bring the revs up in Personal and there’s a different noise there which is good. Drive around in Personal and at lower speeds there’s a slight drone to the exhaust noise, but it sounds pretty good to me. Im still running my car in, so not going over 4K revs. No idea what the exhaust will sound like over 4K at the moment. Generally the change was enough for me to think “Oooo that’s a bit better”. The standard X1 M35i rear silencer is restrictive (along with a resonator), so I didn’t expect miracles, but generally opening the valves gives the car a bit more of a beefy sound.