Originally Posted by dan_vector

Front track wider (more front lateral grip) and Rear Track Narrower (less rear lateral grip) - More steering

Front track narrower (less front lateral grip) and Rear Track Wider (more rear lateral grip) - Less steering

Bear in mind that a wider track width raises the roll centre at that end of the car and vice versa.

To be honest I pretty much leave the track width set in 1/8 as per the kit or latest setup direction and rarely change it.