There is a myth that usng a power mic shoves so much power into the rig that the rig transmits much further, thats totally false, it just overdrives the audio stage in the rig and makes you sound like your in a bucket.
However a mic with a compressor is a good idea as it restricts dynamic range and the rig doesnt try to transmit audio content that isnt needed.
Somewhere I have a link to a page that shows you how to mod a battery powered mic to rig power I'll have a look, you connect 12vdc to the mic socket via a resistor and connect a cap in series to the rig audio i/p, if you do this then some other micswill not work.