I installed 620 coil springs on front with a 1" drop. If you car has the original springs, it may already be 'dropped' from weakened springs, in which case the new springs may not show any drop or may raise the car. Same goes for rear springs. If you have to install new components, then go for what you think you would like. They sell a mid-eye rear leaf spring which will lower the rear about an inch from the original stock height while using original shackles. Fronts again, you can get 620 coils with a 1" drop from stock. Its really up to you.
Make sure you check your A frame bushings, Spring perches, tie rods , etc. If you are gonna do springs, best to have new or strong components to go with them.