Adding foam to your pack for comfort.

I have a Osprey Exos 46 and it's a light weight pack and has Minimal foam on it and was wondering if it could benefit by adding some foam to the pack, mostly on the shoulder straps and back.
Anyone added foam to their pack and found it more comfy, I have some closed cell foam I can use, the sleeping pad stuff, or other foam type better ya think ?
Cheers.
Anyone added foam to their pack and found it more comfy, I have some closed cell foam I can use, the sleeping pad stuff, or other foam type better ya think ?
Cheers.