Help sourcing Koni yellow sport shocks for 280Z!

I have a late '77 model 2 seater zed car and am trying to source some Koni yellow shocks. I know these are not available off the shelf but there are companys which will modify the Konis to suit. I have a few questions that I need answered, what are the part numbers of these shocks and who does the modifications, or are there equivilant alternatives? I have looked at the Tokico Illumina shocks, but am not sure if they will fit this vehicle (apparently the very late zeds have larger diameter struts) does anyone know if these will fit?