"Firmer suspension" refers to a type of car suspension system that is stiffer or harder, providing better control and less movement in the car's body when driving over bumps or corners. Full definition
It works with firmer suspension and damping as well as harder anti-roll bars. (ausmotive.com)
However, the ride is really a cause for concern and buyers should ensure that they can live with the extremely firm suspension setup that shakes passengers around the cabin with almost comical force. (autoexpress.co.uk)
This slightly firm suspension set - up translates to some impressive handling and high - speed stability though. (overdrive.in)