Thank you for the kind words ,
The Properties of synthetic oil is different from simple oil , i guess that is why you experienced a sudden change in the behavior of the car. Switch back to 5w40 fully synthetic. Sometimes you should not switch to any oil if you are satisfied with the performance. Try using 5w40 fully syn of liqui moly , its a really good oil but costs round about 4800.
I am shocked to know you cant find liqui moly dealers in ISb/RWP. The official distribution of liqui moly is in I-8 and i buy my stuff from pearl lube gt road , they are official distributor and sell genuine stuff.
About the airfilter , any other air filter except the oem one is not recommened by the company. I am trying out the airfilter and will see its performance in the Long run and give a review after 5k kms. Then i will decide if i wanna keep using k&n or i want to switch back to oem filter. Because there are a lot of different aspects , as dust and petrol quality in pakistan is worst , it may affect the air filter performance in long run and oem filter might be better then this k&n filter . So wait till i write a review on it.
Enjoy 