I heard there was a certain coilover kit that would fit a specific brand shock. Like on ebay they say that item is KONI compatible, is this true?

 

Ground Control offers a specific sleeve set that is made specifically to fit Koni 8040 and 8041 dampers. The diameter of the sleeve is smaller for a tighter fit against the Koni damper body, and each sleeve has a groove machined into the inside of its bottom edge to fit over and capture the Koni circlip for mounting. This eliminates the need for additional parts or adapters to safely use the Koni circlip mounting system.

eBay is not a good place to buy certain items due to the number of sellers who misrepresent the item that they are selling - unintentionally or otherwise. Unless you are absolutely positive that the sleeves are Koni-specific (look for pictures of the circlip groove), then you may be buying the regular Ground Control kit which requires you to buy additional parts for use with Koni dampers. I'd suggest buying from Ground Control directly.