DOES THE HDK SUSPENSION K-MEMBER HANDLE BETTER THAN A T-BAR SUSPENSION?

I can't imagine anybody using a relatively expensive bespoke CF K with a stock chassis, but I can imagine a properly sorted out CF K member being far superior in a high-performance application than almost every aftermarket K currently offered.
I didn't address a few items you noted earlier, one being I believe elevated heat that can be accommodated with HT epoxies, I don't see chopped CF as ideal reinforcement, and without a TB suspension, metal attachment points are limited in number and see fairly predictable loads, (Rack & SB & 4 large mounting points). Another point that has to be considered is the largest single/ densest mass of the vehicle sits mere inches above the K, and the resultant inertia load paths it induces are rather short and simple. I see all these issues solvable with the needed will, and of course time, money, and testing.