The title of the thread says "suspension", so I won't take into account the aerodynamics.
You can do one, some or all of the following (in order of priority):
1) Soften rear springs;
2) Change camber on the rear wheels. I don't know if it's negative or positive. Your rear wheels should be like the front wheels of an F1, you know?;
3) Stiffen front springs;
4) Adjust camber on the front wheels so that they are "pointed inside", the opposite of what I meant on number 2
I think that's all.
[EDIT] You can also change the toe on the rear wheels, but I'm not sure on how it works.