The answer is Yes, depending on the amount of preload set in the bars, they will make the suspension stiffer in the rear. Calvert recommends 1/4 - 1/2 turn of equal preload side to side for all around use. More preload will make it stiffer and not necessarily make it hook harder. The Caltracs also make some noise that can be heard on a daily driver. Calvert has taken all the steps possible to quiet them down by using a polyurethane bushing on the upper roll pin, so there is no metal to metal contact there. Calvert also uses rod ends that have a teflon liner to help reduce squeaks.