you can also check out Car Chemistry inserts i have them and they work well. same concept as RPI silencers.

 

Are there any sound clip/video of the droning?

 

There's another thread about this, and I put a video in that one. It's on page 4, I think.

 

Guys,
Once again - What I am talking about is a 6 cylinder engine BMW 530i- I am talking about installing a Silencer on a 6 cylinder engine OKAY. Yes it will kill the HORSEPOWER (Period)
Dont try to prove your self right by doing a sample test on a 10 cylinder or a 8 cylinder.

If the silencer kills horse power of a v10 by 3 horses, it might kill the horses of a 6 by say 13 (example)

The 8 cylinders barely drone with the RPI so they will never know what a drone is to begin with.

Also smart people,
restricting exhaust gases causes faster ENGINE OVERHEATING


Also,
Try to focus on the problem which is sound (sound waves are invisible) instead of blocking fuel combussion\exhaust gasses.