Please update
I've used these springs on my RV4 and RV8. It's been about 4 years since I installed them on my RV8. It seems to me that piece that had to be drilled and possibly shortened to determine the overall length was available separately. I want to add a little more slack in my setup so I searched for Lynx springs. Apparently Van's is the sole marketer of this product and only sells the complete setup. Does anyone know how to contact the original developer of the springs?