Pakistan doesnt need to rush to the J20 which is a heavy and expensive fighter.PAF could choose to cooperate with CAC to work on a stealth JF17 variant"silent Thunder" with current available technologies:
1.AESA radar
2.More composite material to reduce the weight.The current JF17 used too less composite material,and it has a lot of potential to reduce the weight
3.redesigned nose like the J20 to siganificantlly redece the front RCS
4.fit with novel Chinese advance medium trust engine which is available around 2015 time frame
5.new advance electronic package
6.next genration PL serial AAMs
With these characters,the silent Thunder still is quite competable around 2015 to 2025 in southern Asia.Though the cost of silent Thunder will be much higher than the current one,but its still a high cost-effective than induction of 18 to 36 J20 for the PAF.And dont forget,China and Pakistan can cooperate to export the silent Thunder to other friendly nations which will also save the cost.
True.
China could also a few number of J-20 (say 5 to 10) on easy credit terms. By then, say 20 years, Pakistan economy would have completely transformed itself and return the loans.