Durometer is a measurement of rubber stiffness. So the author says that the Forge ones are quieter. I prefer quieter engine mounts on a daily driver. Stiffer mounts will prevent engine movement, letting you put more power to the ground but it also transmits engine vibration to the body.I'm a bit confused, the blue ones are poly and the yellow Forge ones are also poly but quieter because the durometer is lower?
Looks good on your site.Thanks again for pointing it out. The writeup is up with additional notes and edited pictures. The reference and credit to the original post is also there.