Netgear CMD31T modem

I have done some searching but I cannot find an straight, definite answer:

Should I expect (something near) 50Mbps download speed with the preferred tier in Scottsdale AZ with the 4x4 CMD31T?

In various places at the cox site I see statements that

(a) the CMD31T is compatible with the preferred tier and

(b) Cox "is doubling speeds" and

(c) 4x4 modems "may not support future speed upgrades."

but I don't see anything like "the recent doubling of speed with the preferred tier  to 50Mbps only works with 8x4 modems"