-How many universities are offering it in Pakistan.
Only NED offered it. No idea if it offers on Grad level..
-Which university is best.
Since you got the only option , you dont got choice
-What is the basic requirment
Same Requirement as for other Engineering. Fsc/BSc Specific Percentage + test
-At what stage "Auto Engineering " subject start in higher studies e.g. FSc /BSc or from MSc.
Depends where you want to start from. Usually it starts from Undergrad