ORIGINAL: dannthenitroman

If your car needs more grip at either end, you should try softening up the suspension at that end first (assuming the suspension has shock oil in it, cos shocks can be leaky, and if theres none, well use your imagination) by using softer springs , thinner oil, or larger/more holes in the shock piston.
Alternatively, we can use leverage instead. Think about a second order lever (a suspension arm levering a shock shaft), if we consider this, the closer the shock is to the chassis the less resistance it will offer to the suspension arm, for example if the shock is mounted at the wheel it will be EXACTLY 2 times as hard as it would be mounted in the exact centre of the arm, and another half as hard again if it is mounted only a quarter of the way from the chassis.
So for minor changes (usually whats done at the track as the setup is probably right, we are just accounting for the conditions of the day) this can be used also.

Another thing to keep an eye on is that when the shock is mounted closer to the chassis, again due to leverage we can see that the car will have more suspension travel in both directions, particularly down.

If you have a good idea of geometry and the dreaded vector, we can quickly see that changing the angle of the shock also influences its resistance applied to the arm, if the shock is in a more 'layed down' position, the shock will also be in effect softer. There are a lot more complicated traits that each of these adjustments do also, like comparing traveled angle change for a more layed down shock (consider how the angle of the shock changes as the suspension compresses), but these are things only the hardcore racer needs to know and cares about. Not necessary to know here.