One thing I've never understood about lowering springs. Most of the ones I've seen lower the car more at the back than at the front. Out of the box, cars sit higher at the back and your typical boy racer objects to this and wants the car to sit flat, so most spring kits are aimed at achieving that.
But the thing is that most boy racers are idiots! There is a reason the car sits higher at the back. Shock horror, car manufacturers have thought about this. If you make cars that way, they look right at all times. Forget about when there are people in the back, just driving along will put torsional force into the car which will pull the back down but because it's higher at rest the car still looks fine.
Unlike your typical boy-racer buggy. They look at their nice, flat car parked at the side of the road and think it looks the dogs but don't realise it looks broken when it's in motion. With their mates in the back it looks like a guinea pig wiping its backside!