A mat of any benefit for a VPI Nomad?

Just wondering if the hard plastic mat on the VPI Nomad is sufficient or would say a Herbies mat be better. Some say that the Herbies mat in some ways improve the sound and in others if make the bass not sound as good, over dampen. I have a pair of Grado rs2i headphones connected to it with a Grado Reference Platinum. Apparently VPI does not buy into aftermarket mats. Gerald.