I've currently got d2 in my r33, they are bumpy but for the price i pay they are a good entry level coilover (i have the track spec ones)
I have done drift practices, mc days and a few other sprint days; and found the car to handle pretty good. Im about to upgrade to Tein Circuit Master Type RS, as im looking to get more hardcore about my track time
I think you will find most china spec entry level coilovers will be pretty similar if not the same (they are all pretty much made in the same factory). Most people comment on how bumpy and hard the ride is for j-spec coilovers (hks,tein, trust etc etc) but i think it something you just get uses too and if the coilover is of good quality the damper adjustment should help to reduce the hardness of the ride