Coilover
 

What is the best coilovers for just smooth driving and really low stance. Any good suggestions ??

Really low and really smooth don't really go together well. As you get lower you need a stiffer spring rate to absorb the same amount of 'bounce energy' as compared to a longer travel (stock height) suspension. Bottoming out the suspension is not a good thing for driveability or car control. FWIW: I like my Ohlins, stiffer, adjustable height, and smooth riding. But you pay to get the great combo.