Radios do not come with roms they are separate areas of the phone. Besides half of the users running the new radios are reporting worse signal coverage.
Actually, I flashed the "leaked" updated one (found it here: [DOWNLOAD] New CDMA/LTE Radios for the Galaxy Nexus)
It's only been a day or so, but it seems to be a bit less inclined to lose signal. YMMV.