No matter what springs you get, your ride will be shit if you use stock shocks.
Upgrade your shocks and springs at the same time if you are concerned with ride quality....
Stock shocks cant dampen the higher spring rates of aftermarket lowering springs, the end result is a bouncy car.......
Want a good ride? go with a reputable spring manufacture (not ebay brand shit) and a quality shock that matches the spring rate...
Want a lowrider? get cheap ebay springs, remove the bumpstop, lower the car 5" and ride like a baller.....(not really because you will look like an idiot)......
If you absolutly don't want to swap your shocks then go with a lighter spring rate from ground control or like.