Based on what? They will go for the early Pak Fa based on the current T50 prototypes. Engine is ready an proven, radar developed and integrated, NG EW newly developed and now under testing and integration, weapons beeing upgraded and modified for the use from weapon bays, general flight tests completed, in flight refuelling and external payload tests done too...
We surely will see weapon launches from external stations and first test from internal bays later this or early next year, which will give a better idea about the payload capability and the use of the fighter in different roles. It will be interesting to see the final EW config, especially how MAWS and DRICMs can be combined, but all that does not cause major delays from the Russian plans to get the fighter around 2016.
If you compare all this development, integration of systems and testing they did in the last few years on a NG fighter and compare it with what our industry did in the same time with LCA development, integration of systems and testing, you understand the huge difference in capability between them and us!