Yeah, you can do that. The cup kit is good, Eihbach is good as well.
You wont have clearance issues with oem or aftermarket springs provided you don't drop it more than 2.5" in the front and 2" in the back, but i suspect with a firmer aftermarket sping you have less potential for rubbing during a spirited romp.
Springs will run anywhere from $180-300, so you could feasibly buy sport shocks and springs for less than say the PSS9 coilover kit from bilstein.
Coilovers are nice though, i have enjoyed them on previous cars and intend on adding them to my current sled.