Flashing a radio can greatly affect your device. It can improve signal strength, improve data speeds, or even help with things like call quality and alleviating dropped calls. On some devices which have radio bugs on release, such as complete loss of signal, a radio flash can alleviate these issues and restore stability to signal. However, and especially on HTC devices, a bad radio flash can easily result in a very expensive paperweight.
With that in mind, XDA Forum Member nolimitzr2 has posted a thread with the latest radios for the HTC Rezound, pulled from the latest Android Ice Cream Sandwich RUUs. The radios, which users can install using pre-compiled PH98IMG.zip files in the bootloader or individually, come in multiple flavors including the tried and true Gingerbread radios as well as the new leaked ICS ones. Users would do well to download both in case they should want to switch back to the old radio. Users intending to use these should proceed with caution, says limitzr2:
Your mileage may vary these havent been tested in every combination of Hboot\Firmware\OS so there may be issues. However I will do my best to update this post of any known issues.
So there could be some compatibility issues depending on what your individual Rezound is running as these radios are largely untested. Also, as many HTC owners already know, a botched radio flash can cripple a phone and leave it bricked so be sure to check the MD5 and be sure your phone is in no danger of accidentally turning off or losing battery mid flash.
For more information, the download links and the thread discussion, check out the radio thread.