While they sport a stiffer rate than stock, the 450-lb/inch front springs in Naake’s Marauder kit are shorter than stock (10 inches tall free height, probably 2 inches less than stock). For a cushy ride and reduced NVH, stock cars are usually equipped with soft springs with lots of travel. When you lower a car, you lose much of that travel, so spring rates need to increase to keep from bottoming the suspension. The QA1 tech guys recommend an installed height of 75 percent of free-standing height. In the case of my 10-inch-tall spring, they’d prefer it measure 7.5 inches in the car on level ground. The 450-rate springs were slightly less than that, so they supplied a pair of 550-lb/in springs that conform to their 75 percent guideline, as seen in the picture.