You say you want 1.5" drop, a smooth ride, and to keep your stock shocks, but you're gonna have to pick two. If you want 1.5" drop and a smooth ride, the stock shocks aren't gonna cut it. If you want stock shocks and a smooth ride, you're not going to get a 1.5" drop.
If keeping the stock shocks is your priority, get the VWR springs. They're about a 3/4" drop, but ride quality is good with stock shocks. If you don't mind getting new shocks, too, then pick the springs that give the ride height you want.
and for that kind of money, you might as well go with coil-overs!
Disagree. I'd take a good spring/shock kit over cheap coilovers any day, especially for someone who's concerned about ride quality.