If you are concerned about quality, the cause is already lost, whatever sound editor you use. The person who sent you the Wav file should have recorded at the correct level for a start, then Normalised it before burning. If you do this then the digital recording uses all the 16 bits of data available to record the instantaneous volume of the track every 44.1 thousandths of a second.
If the signal recorded was 24dB down, the last four bits will always be blank, and the recording will have random errors where the sound level is not quite a round-number value.
That is noise, and it is now part of the recording. When you boost the signal, you boost the noise as well.
Incidentally, "Maximise" does more than boost the levels. The term is generally used to include a type of compression which aims to keep adjusting the amplification all the time to keep the signal close to the maximum the whole time. In other words, it is turning down the loudest bits and turing up the quietest, reducing the dynamic range.
On the other hand converting to MP3 involves some compromises on quality anyway, so it may not matter to you.
Cheers
Dave