Good article. But there is a misconception about Aryans that has been created by Britishers.
There was actually never an Aryan Invasion in India. Aryans were the people living in northern part of India and still live here. Just like Dravidians were from South India.
There were many different tribes in India other than these two. These tribes differed from each other mostly because of their inclination towards specific Gods and thus having their own customs. But that does not mean, they used to cut each other. The culture and Gods were the same but the inclination varied.
The customs being followed were highly affected as per the region these people used to live in. India is diverse, some areas relied more on sunlight for their survival and thus people living there were more inclined towards the Sun God, you can call them Sun worshipers as they admired more Sun's light and temperature as per their region's requirements.
Similarly, areas getting lesser rainfalls used to worship Indra and Varuna (gods of thunder and water).
Aryans were mostly the Shiva worshipers. No one brought Shiva from outside, Shiva was already worshiped all over India. But Aryans being a fighter race (Kshatriyas) were inclined towards Shiva and Kali.
One more fact, The Native Indians in America are also known as Aryans. I am not really sure why, but someone might be more interested to look into it.
RE: A Brief History of Ancient India