Not sure which (red) Koni shocks you are referring to, but I have an (orange) set of Koni rear shocks on mine that I bought NOS on Ebay a while back, that work wonderfully. I don't recall mine being adjustable, (if they were, I didnt change the setting) but they are just right for me as far as firmness. They are firm without being bone jarring harsh.They were a vast improvement over the OEM Gabriel "adjustables" that were still on there!