I have soundproof my both car, but i only have installed 2 layers in the door. It can help you to reduce the road noise & vibration. When u closing the door, u can feel your door is heavy & the closing sound would have reduced.

For rattling sound, u need to identify from where its coming and fix that part. General soundproofing solutions maybe wont help the rattling sound part i guess.

Use good quality tyre which have low noise. This really helps.