If you listen clearly to the mantra Om Gum Ganapatayei Namaha in the video recording by Sadguru Sant Keshavadas,
The Ganapathi bija is pronounced as 'GuMmmmm....., Where it is nazalised, it is not Gum as in 'chewing gum,' but more gum to rhyme with the English word 'Numb'
When the Ganapathi bija is pronounced this way with the correct anusvara termination, I feel it is certainly more powerful than Gum as in 'chewing gum,' and probably more powerful than pronouncing this bija as 'Gung' to rhyme with the English word 'sung!'
This Ganapathi bija as 'Gung' to rhyme with the English word 'sung' stimulates the 3rd eye and Crown Chakras, whereas The Ganapathi Bija pronounced 'GuMmmm' to rhyme with the English word 'Numb' stimulates the Heart,3rd eye, and Crown chakras, adding even more power to the results from this mantra!
Namaste,
Billy