Yes the rear will be higher than the rear. This will cause the front to nose dive and become bouncy. While you can do just the rear springs with great success (doing just rears is definitely better than OEM springs all around). We highly recommend doing both front and rear springs on the vehicle. This is because the vehicle has handling dynamics that are affected by the front and rear spring rate relationship. This is called the motion ratio of the vehicle. When the front goes over a bump the whole chassis is like a lever arm on the rear springs and same goes for the rear in relationship to the front. This movement or transfer of energy is what is defined as the motion ration of the chassis of the vehicle. Things like corner weights, wheelbase, width, suspension travel, suspension height, strut length, etc. all play factors into the motion ratio of the vehicle. When you do just rear springs this balance or ratio is skewed out of normal or ideal operating conditions. We at Rallitek have a company vehicle for each and every vehicle we design parts for. We do this because we want to bring you the best performing product money can buy. This motion ratio is critical in our design process and makes for a much stable and composed ride quality and handling. While doing just rear springs is not something that will damage or make for a safety hazard keeping the motion ratio of chassis within the ideal operating range is better in the long run. Basically when the rear goes over a bump it transfers energy into the chassis causing the nose to dive naturally (newtons law with every action there is an equal and opposite reaction) if you do stiffer spring in the rear the rear suspension will resist this bump more so than a factory spring would thus transferring more energy into the chassis and more energy pushing down on the front springs. If the OEM springs are in the front of the vehicle this will cause the front to compress more than if our Rallitek spring is used. The imbalance in spring rate will cause the nose to pitch down more and will cause an oscillation in the front springs as they rebound from the energy pushing them down. This causes a bounce to occur in the front (often times it’s barely noticeable but that depends on the vehicle and the motion ratio of said vehicle). Rake (front or rear being a different height than the other) can cause the same thing to happen.