This is the most powerful and popular Mantra. The combination of the three Bijas means it is addressed to the Supreme Deity Chandi as enunciated in Devi Mahatmya. This is also known as Chandi Navakshari.
The difference between "Om Aim Hrim Klim Chamundaye Vichche" and "OM AING HREENG KLEEN CHAMUNDAYE VICHCHE" is because of the way the Bija mantras are pronounced in South India and North India. Everyone swears that his pronunciation is correct.
This is an ideal mantra for reaching GOD. If you are using it for spiritual advancement, you do not have to bother about pronunciation.
MAA is Dayamoyi and Karunamoyi. It is ridiculous to think that MAA will punish you if you mispronounce the Mantra or do not have concentration.
This canard has been spread by Pundits who wanted a monopoly of the Mantra Yoga and did not want others to reach GOD. They are/were interested in ensuring that anyone who wants to approach GOD does it only through them after paying a hefty commission.
Death is a punishment in the Abrahmic religion. Death is deliverance in Hinduism.
About the use of this Mantra for other purposes, all mantras can be used for various purposes. It is not the fault of the Mantra. Nor is it designed for that. For example a hand Gun can be used to protect yourself from harm. It can be also used for murder. It is not the fault of the Gun.
Kali_Upasaka got a reaction from Raveena in Navarna mantra