Tim.
On the picture above provided by the Spain shop :
The Yellow is the front cartridge "sport" series, the Red is the rear damper "special" series.
From the Koni FAQ :
Quote:
Q: What is the difference between KONI Special (red) and KONI Sport (yellow)?
A: The KONI Special (red) has been engineered to maximize the ride comfort with good handling performance for each vehicle application. The KONI Sport (yellow) typically starts at a higher initial valving baseline to give a sportier feel and work on vehicles with higher performance parts. In some instances, KONI will only offer a Special or Sport valving and not both. Some modern cars come from the factory with higher tech suspension systems and wheel/tire packages so they would move directly into the Sport range, however they are still valved to give a comfortable ride with very good handling capabilities.
From this picture, i can tell you the rear damper is rebuildable. Same Yellow sport construction, removable plug on top...
So maybe revalvable latter for higher performance.
Only the Sport Yellow is valve tuned for lowered spring, like a B8 from Bilstein.
The Special Red is valve tuned like a B6, so lowering spring could kill it rapidly like my GR2 with H&R 29710 lowering spring :
My rear GR2 are dead, clunk on bump and bad efficiency, i upgrade my damper setup front and rear.
I don't know much about progressive VS linear spring, the Koni Technician only confirm me the H&R 29710 kit is the best spring setup available for the Koni Yellow sport.
Maybe an European mind about the worldwide market.
I have revalved +20% my rear Yellow damper's accorded with Koni technician for improve the performance on hill race application