Is it normal for all springs to bow under load?

Some brands of springs "bow" excessively under load causing them to make contact with the shock body. This contact not only affects the car's corner weights but also puts additional heat into the shock through friction between the shock body and the coil. Some manufacturers have tried to put a band aid on this problem by using a plastic sleeve to stop the bowing from wearing the shock body. This may stop the shock body from wearing but anytime one of the coils rub the shock body / plastic sleeve the effective spring rate goes up considerably, and the car's handling changes. All Hypercoils are designed and manufactured to resist bowing under load.