I read somewhere that you could use the .mp3 proximity alert for your speed traps for instance. I use the Nokia wav audio files but it seems to be too quiet. I dont know if the .mp3 will play louder or what. If not, is their a way to boost the volume of the .wav file before it is loaded onto the nuvi?
The simples way to increase volume of wav file is a standard "sound recorder" program in Windows. File-> open, Effects->increase volume. You can do more precise work in any sound editor as well.