I use 5kg springs in rear. Very soft and I have quite a bit of droop.
I have been watching a heap of the videos ole mate did with his carbon 240z.
Now having a go learning carbon.
If all goes to plan I might make a fuel cell to sit right behind rear towers and mount my wing off the cross between the towers.
Then I have a bucket load of space under there and we may go to a double wishbone style set up, or at least some sort of locator behind diff.
can’t wait to cut all that metal out. Carbon Skin is 2kg