buddy club racing spec suspension

[clutch_cargo]

hi i just bought an ae111 bzr levin, the car runs great but the settings for the suspension is too hard at the rear, the current suspension set up are Koni yellows inserts on the front which are set to firm (no probs here) and buddy club racing spec dampers with a 5k coilover setup which are set to hard (car prolly ran circuit in japan)

the ride at the back is very twichy and the car jumps at the slightest bumps, it is very dangerous to drive this car at high speed on unleveled roads.

what i would like to know is how do i adjust buddy club racing spec dampers as to soften the dampening at the rear?

thanks in advance