Well, they have different style(s) for use as an isolator, insulator and/or spacer, you just need to figure which way you wanna go.
I think this is what you are after to just insulate the lower coil from the arm to prevent any noises. They have upper isolators also.
- Ramped Coil Spring Isolator Set -
Coil-overs is another method that will ease trim height selection and stiffness -