My approach is both
- Purchase 2 Squadrons of J-31 , to help mature that platform (Attain within 1-2 years and refine to Block 2 by 2021)
- Invest in the TFX project , for a alternative strategy (8 year projection)
- Designing a 5th Generation plane from scratch 100% cost would be high no doubt (Local Path)
It would make sense to be part of the J-31 , platform since we are already connected to China , and help mature this platform it can be integrated immediately , and Chinese can help develop the Block 2 of this Jet , of course we would benefit when that happens. (32-40 Fighters). The J-31 is
"flying in air"
Now the Turkish project looks interesting however , folks have stated it will take 7-8 years for it to finish. Investment $$ from Pakistan side
would make sense put $$$$ commitment into project no brainer this is being designed from scratch so will take time.
Hopefully around 2025 , we can be confident which platform is ideal to replace F16 Jets we have