@hasankhurshid29 yesterday I got my car inspected from another mechanic/expert. He seems an educated person and have worked on different cars in different countries throughout his life. Most of the times, his workshop is full occupied by the SUV's and German cars.
I explained him that rumbling issue and told him that i have replaced the clutch/pressure plate set and this issue arose after the work done. Good thing is he noticed the vibration within a minute he sits in the car. He also says that the vibration is travelling from the floor and must be from the gear box. He tried to explain me that how much matting (clutch plate and flywheel) and balancing is important which is not done in my case.
He suggested me to take it back to the same mechanic and ask him to reopen and face the flywheel ensuring proper matting. To which i replied that the previous one is endorsing the issue even why he would open and do all the stuff again. Plus if this is the issue im not going to give him the car for test and experiment. Im going to give the car to this mechanic as in the past I got two of my family cars clutch plate/pressure plate work done from him and found them to be perfect with no vibration, jerking issues. His labor is bit on higher side but Im thinking to give him a try.