Both Fiat Grande Punto and Volkswagen Polo fall into premium hatchback segment. While the Polo sets benchmark in the segment in build quality, fit and finish, ride quality and handling, Grande Punto fails to impress in most of the departments. Punto's proven 1.3-litre multijet churns out 90PS power on paper but fail to deliver on road. That is why, we will suggest you to go with the Polo.
Sir, if all the engineers are saying that there is a problem in Punto than they might be right, then you should test another Punto in same variant for that problem. If you feel the same problem in the other car also than the engineers are right. But if you won't found the sane in test vehicle, then there Might be a problem with your tyre or wheel or it might be a problem in suspension system. If the problem is with tyre, then it is a regular problem. But you are saying that the problem appears when it just jumps over a bump. By this, it is sounding as a problem with suspension system.