I have no noise with my Mugen suspension.....
As far as adjustable coilovers goes, if you set them soft then you get a bouncy ride, set them firm and you get a harsh ride...
but i do like the fact that you can raise or lower based on the area your driving... but i think that setup is more for the control freaks out there

I don't have the patience to fine tune my suspension...
Kegster