How this coopration may change the regional balance of power and if the Persians deciding to such variant of cooperation will be able to protect themselves from the political protectorate?
I think that after the oil embargo is lifted, China started buying again, Iranian oil as in the past as well as other raw materials and China will increase the exports of high technology in different sectors, including the nuclear sector.
There has been already a power shift in the region where the U.S. seems to have lost much control. Definitely, Iran will have much closer relation to China because China has a much better leverage than the U.S. in the region. Regional grouping cooperation is an advantage for Superpower like China, which loses no time to go after given the current weakness of the U.S. in soft power diplomatic leverage in the region.
It is vital to understand one important fact that China rise as an economic and military power has already influences the statuesque and balance of power especially in Pacific Ocean and surrounding areas. In the Iranian case, the attitude of both sides will determine the future Iranian geopolitical directions. In the last few yeas, the Iranian collaboration with China was build on out of necessary in order to assist Iran getting out of long term isolation. However, currently the Western opening toward Iran may open the door for another geopolitical shift in favor of West but this remains to be seen how far Iran and the West willing to invest into this new approach.
With China's influence in the region, the West has no other choice than to have a soft power diplomatic approach with Iran. Isolationist approach would not be right approach for the West.