The set up on the rear of the Mk3 and 4 Escort means that the outside rear wheel start to "toe in" when you turn into a corner and the harder you corner the more "toe in" you get = understeer, so the front have to work harder!
If the car has been lowerd and the rear tracking has not been reset or improved the the car will be very unresponsive.
This is a small guide, without giving all my gained experiance away.
Simon.