The Bullitt springs shouldn't be used for lowering a car, since they only drop the car about 1/2" over stock, and they shouldn't be put on a V6, since their spring rate is calibrated for the heavier V8 engine in the front.
A number of companies carry springs that will drop a V6 about 1". That's about where you want it- gets rid of the 4x4 look, but won't require castor/camber plates or look too "slammed". Their spring rate will be correct for the V6, too.