DOES THE HDK SUSPENSION K-MEMBER HANDLE BETTER THAN A T-BAR SUSPENSION?
Both systems can perform extremely well but, for the vast majority of us, to make the torsion bar system work requires replacing or modifying most of the TB system anyway.
It ends up being a long way from stock to get the performance these guys are getting.
Its useless to use TB and factory K-Frame without removing it and rewelding all the seams and installing the required gussets. Boxing LCA's , replacing Upper control arms with Tubular , experimenting with T-Bars , Installing a better sway bar, upgrading shocks, upgrading steering box to Firm Feel specs or going with a Borgeson replacement.
What you describe is effectively rebuilding the suspension. Let me paint you a picture.
Let's say you buy a basic '75 Duster /6 that is pretty well used up. When you pull the suspension apart to rebuild it, you find a LCA pin has broken loose. So you pull the k-frame to get that welded up. Might as well fully weld and gusset it while it is out. Or even better, find a V8 k-frame and get it gusseted and welded before swapping it. And if you are going to rebuild the LCA, why not put poly or better bushings in. And stiffening plates are an easy upgrade at the same time. Bolting the LCA back in, why not use adjustable struts since the poly bushings cause problems and you have to buy parts either way. Shocks are absolutely junk, so why not upgrade? UCA bushings and ball joints worn out? Buy some new ones. Torsion bars all sagged out? Why not put some bigger ones in? Car didn't come with a sway bar, so buy an aftermarket one. Steering box slow and/or worn out, why not a Borgenson box? Other than brakes, wheels and tires, you are done. I don't see that as a long way from stock.
In regards to the gusseted k-frame, I basically went through the above. My '74 had a pin that was breaking loose so I bought another spool mount k-frame and had a buddy gusset it and weld it up. Figured while it was loose, it was the right time to do it and buying another one meant I didn't have to leave the car on jack stands for awhile. Then I swapped my k-frames in a weekend or so. That k-frame then went back to the same friend and he fixed the pin and welded/gusseted that one as well. My G3 swap car is a /6 car so that k-frame got swapped into it. So I now have 2 cars with gusseted k-frames all for $100. Not counting the work my buddy did because we help each other all the time, benefits of a lifetime of friendship.
I think you are looking back at it through the lens of having spent a fair amount of money and kind of blowing it out of proportion. At the same time, I am certainly looking at it through the lens of not wanting to drop all that money all at once. I have other reasons as well, and not going to say the cost couldn't be influencing those reasons even though I don't think so. I just don't see the ROI.
In regards to ROI, and just so I am not confusing anyone on my stand or financial situation, my curiosity with the DSE, G-Comp or full chassis stuff is only that. Curiosity. I don't see the ROI on using one of those options
for my uses. The blue Valiant is wicked cool and in my mind that makes complete sense for that build. Maybe integrating a G-Comp setup into the front of a car if I was building an all out build but didn't want to or couldn't do a full chassis like that Valiant. Something like a competition venue where a 315/30R18 is a must to be competitive. I would love to do some of that stuff, but I wasn't born with a silver spoon in my mouth so I just don't see it on the radar.