Whilst certain occasions will demand the fitment of a ‘higher stall’ converter, whether or not you NEED one is a personal decision. Almost any auto vehicle, even those with giant camshafts, could get away without upgrading the stall converter, but the power, speed, drivability, and safety on braking etc of the vehicle would be severely compromised and far from optimal.
The fact of the matter is that if it is time slips and going as fast as you possibly can that you desire, then an appropriately matched stall converter to your setup is the optimal way to do it. In saying this, if it is numbers on a the dyno that you care about, putting a race converter in your car, whilst inevitably making the car faster, will output far less impressive figures on a chassis dyno compared to a vehicle with a standard stall due to the principles of how the torque multiplication from the converter works with the dyno.
An appropriately matched converter for a vehicle 100% makes the vehicle infinitely better to drive – choosing the size of the stall is something that we can assist with, once again, after doing some investigation into your desired outcome.