need advise on spring/strut combos!

I want to upgrade my ancient performance spring strut package in my 71. I like the price of the Tockico spring/strut combo that is being sold on EBAY.

But I have heard folks on this forum say the Tockico springs are progressive rate and maybe not the best for performance. I will be driving on backroads only, no autocross, but want good performance vs. smooth ride.

I imagined the tockico package would be a good route because the pair were designed for each other.

I have heard the Suspension Techniques are a good chice for springs. Would they be a good match for tockicos, wither the regular or adjutable Illuminas?

Finally my old springs are yellow, I think they are suspension techniques anyway, but I beleive they are pretty old. You think I need to change them out to begin with.