Upgrade engine?
-Yes a No. The 1200hp original engine is still considered a good one, especially when you compare to Indias T-90 and T-72's 730hp.
Improved optical/thermal sights from Ukraine?
-Yes, Ukraine has already fitted their T-84 mbts with western optical sights, SAGEM 15 (Used by the Leclerc and Challenger 2) in a bid for the next Turkish tank. They already have the tech know-how, and a boost from western optical sights and FCS would be very much helpful for PA. A recognition range of 4km with western optics over 2km is a major difference between life and death.
The 125mm smoothbore gun is fine imho, Ukraine is known to produce better guns and engine than the Russians. Lets not forget that after the fall of the Soviet Union, Ukraine was left with a large stockpile of war machine and military inddutries; Nuclear weapons, cruise/ballistic missiles, Flankers, Migs, Navy carrier, ships and tons of armor technology and engineers left behind for them. Dont worry Pakistan knows what they are dealing with when going to the UK's for military technology.:thumbsup:
T-90 = Russian upgrade to the T-72 series.
T-84 = Ukraine upgrade to the T-80 series.
-Both are entirely different tanks and turrent design isnt similar from one another.
Just improve the FCS, optical sights, a more modern data communication/navigation system and armor and the AK2 will be just fine imho.