To be honest most people wouldn't notice when driving on the road.......it's not likely everybody drives on the limits of grip all the time they are driving to work or the shops.
Being a regular to the track, (not so much since the clutch failed though), the panhard rod has proven to be very helpful in keeping a good handling balance through corners. With a standard panhard rod, yes the car drives and yes it's perfectly acceptable on the road........however on the track there was a noticeable discrepancy between left and right handers, which would make judging entry speeds harder, as the car would tend to corner better one way than the other and also be less stable over rises and dropoffs on track at speed.......Brands Hatch is a pig for this! The adjustable panhard rod has helped to straighten that lot out and the car is now more balanced.......not prefect due to it being 5-link, but improved none the less.
As people say, the more you lower the car the more pronouced the affects are, but it's not absolutely necessary.