Tusas was given contract by Lockheed Martin USA to upgrade PAF's fleet of older F16s (the F16 A/B block 15 aircrafts which we acquired in 1980s)
they will be upgraded; airframes will be renewed, avionics and radar improved. Also I believe we will get the Lockheed Martin Sniper targetting pods
All F-16s at the PAF inventory will have the same standard of operation, meaning compatibility and usage.
PAF will get 18 new F-16s which will be 52 or 52 + by 2010 hopefully
This means old upgraded F-16s will also have the same configuration as new F16s --and with new AEW&C aircrafts establishment of data-link will be possible
It is believed that 2 F-16s will be upgraded at Tusas facilities and the rest in Pakistan probably Kamra or Sarghoda
A total of 14 block 30 F-16s were delivered to Pakistan by US, as aid and all have arrived as of July 2008. I am assuming those are included in the Tusas services tender
Special kits mean, the upgrade kits, these upgrade kits will be integrated with the assistance of TAI, Pakistan does not have the knowledge, expertise and integration permission on there own by the US, that is why the work has been tendered to TAI after competition --since TAI is licensed by Lockheed Martin to assemble and upgrade F16 airframe/engine/etc.
It is 46 aircrafts in total (if i am not mistaken) that will be upgraded and delivered to Air Force of Pakistan
hope that helps