i've owned the SPL coilovers on one of my previous Z's which had kyb/eibach before i had the spls...it is DEFINITELY stiffer and you will feel more bumps on the streets but i did not care, the car handled like a friggin champ! sure its not a zeal kit or anything but wow the car was amazing. it was simple enough to install myself as well so that was a plus. no bushings/gaskets to rumble about. Again i drive on very bad NYC roads and i felt every pothole, bump, divet etc but i also drove on stock 16's for i wouldn't like to ruin my wheels and it was my daily driver. For my next Z i am definitely going coilovers again and it'll be a weekend car so i will get bigger wheels, im not worried, as long as you dont drive like an a&& and fly down horrible roads, your ass/back wont suffer the bumps as much. go coilovers definitely! and i highly recommend the SPLs