Actually, folks, a very good source on these people and their times is EMPIRE OF THE STEPPES, an out-of-print work by Rene Grousset.
Dr. Grousset was not able to write much about the Aryans, as they were illiterate at the time of their conquests, but the history of other conquerors and notables in the Xinjiang region makes for gripping stories.
One such was Pan Cha'o, a Han general who was possible the best military mind of his time. His military and diplomatic skills deprived the Huns of any assistance from these Xinjiang towns. (about 70 A.D.) Also mentioned were the Mongols of the House of Jenghiz, Tamerlane, and the later Buddhist Mongols not of the line of Jenghiz, such as the Oirats. Even later in history Muslims lived alongside pagans Mongols, as in earlier times the brilliant Kuchean culture was literally a couple of day's ride from the most warlike of horse barbarians.
All of these added to the history and culture of these parts.
Even the Russians were there in later centuries: the book tells of a Russian army (1720) being driven off by Galdan Tsereng and 20,000 Dzungar fighters, although the latter had only bows and arrows, and the Russians firearms.
The biggest flowerings of culture in this area were in around 600 C.E. when the region was profoundly influenced by India, and later, in the 16th Century under Islam.
In the first era the town of Kuqa ("koo-sha") was known for its hospitality and dancing girls, as well as a high level of culture. The T'ang regime of Emperor T'ai Tsung demanded and got homage from these towns. For the most part they were left alone.
This ended when King Hari Pushpa (Divine Flower) got into a very ill-advised rebellion against China. The town of Kuqa's army got wiped out fighting the Chinese, and their noble class apparantly got wiped out too, ending their era of greatness.
A century later, at the Battle of the Talas River in 751, the Chinese army of these parts was defeated by the Muslims. China, also beset by Tibetan attacks and the rebellion of a Mongol mercenary named An Lu-Shan, lost Central Asia for a thousand years.
Later on, after Tamerlane's empire had faded away, the area saw a great flowering of Muslim culture. This in turn faded away in the 18th Century, when China came back to reclaim these lands.
As Grousett said of Xingiang, "...this land, in which the Chinese have stifled national characteristics and qualities, which they have jealously closed...."
Chris