This thread has been going a long time and I may have explained this earlier but a bit of product development info......
I first looked at doing modified main control arms. Took the stockers off and showed them to a stock car and hot rod builder who strictly does custom chassis & suspension work. My plan was to fabricate tubular arms but he told me that a fully boxed rectangular section arm was just as strong as tubular. Plus there were other issues I was uncomfortable with: how to mount the end link; installation of main arms requires dropping the subframe for bolt removal; potential failure due to the fact that the main arms carry the majority of the rear suspension loads. Then add in the fact that the stock Ford toe control arms are flimsy, disposable products, relatively simple to install and the decision was made for me.
There are some comments & opinions of the tubular TCA's on the NECO board by at least 1 fellow who autocrosses his Cougar. If you cannot find it PM me and I'll see if I can find the link.
Redcoat Raceworks. Performance parts and custom fabricating for Contours, Mystiques and Cougars. Specializing in chassis and suspension parts. Custom end links, control arms, strut tower bars, engine torque braces, etc.
