My previous car (which had Coilovers), I'd take it to a specialised Tuning company quite regularly. I was advised the car should be a fraction lower at the front end, with the rear slightly higher. All to do with correct handling and weight distribution. Not just for cornering, but also when you are applying the power and braking (especially for front wheel drive cars/engine up front!).
Want the car to handle and ride at its optimum, suspension geometry should be configured with the front end riding slightly lower, however want the car to look "cool" with a loss of handling performance, lower the rear end more extensively.