Either radio will do what you want. If air is the priority you will need to get a new antenna for each, as the standard antenna is a try to do everything antenna that is aimed at an average frequency higher than the standard air band, and works best in the upper VHS, UHF, and 700-900mz range.
The decision between radios depends on how much you want options like recording, full inboard database, and other options that use an SD card.
If you don't want those options, which come with maintenance of an SD card and the issues that presents, then get the 325.
If you want those options, get the 436.
Either radio is equally capable on receive. One other item, owning both, I find I carry and use the 325 as a portable more. The 436 is portable, but twice the size.
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