A while ago me and my friend lowered my car more in the front, now almost maxed out on my KW V1s. While lowering my car he asked me about adjusting the preload because he couldn't find out how to adjust it on my KWs and assumed that the preload gets adjusted with the height.

When I started driving on the freeway at about 70-80mph the ride gets extremely bumpy (even on smooth roads) and it doesn't seem natural. While I'm driving I can see the light from my headlights vibrating up and down.

Any idea of what could be the problem, does it have anything to do with preload? or is this just natural?

 

When lowering your coils you want to keep the spring compressed the same as when you got them, if you just cranked down the adjustment sleeve to get it lower your spring is now over compressed and you'll bottom out the shock much easier. I'm not sure about KWs but my Megan LPs are about
1/4" compressed w/out any load on the shock for the preload F&R.