Only drone if you listen out for it, not really noticeable at all to be honest so little drone which I was surprised after hearing how loud it sounded.
Design is supposedly relatively similar to OEM, they have used same circumference/diameter down pipes. However they said OEM full system have a lot of bends If I remember correctly. Therefore they said they would require modification to make as it's different from M135. Valve is located at the tips, they also fitted anti-rattle clamps to the tips to prevent any loose or rattling to come in say a few years.
Big difference from cat-back to turbo back. Valve is noticeable just becomes deeper note.
Other than that they said was pretty straight forward, I have asked about the power increase.
Doing a resonated version or non-resonated.
When I get underbody hi-resolution photographs il upload them
