Wheel, not sure if you're on a total budget focus, or just wanting to fix the items you've innumerated. What you've heard about Fatman stuff concurs with most of what I've heard too. The folks that seem to be most satisfied with his stuff are focused on the price side, not the quality side. I'm surprised to hear anyone negative on Heidt's. I've used several, and the stuff is top notch in quality, build, and appearance. The only time I heard a complaint was when a guy installed it wrong. I don't believe they make a clip though, except the bolt up one for early/mid Nova's. With a front steer I think you have the '68+ Nova, but maybe someone else knows for sure. The Jim Meyer stuff Richard suggested is also good quality. Although with the morphed frame you already have, your options are limited.

If what you have is done right there are ways to make it work. First the right part. The driving well that you've already noticed is a good thing. But you may want to lift the rig up and do some measuring to make sure it's in there square. Looking around at the suspension components, you want to look for a bunch of shims at one side, or corner, vs the other. That could give you a hint too. If it's in square, and the welds at the joint of the clip and frame are of high quality and well gusseted, then I would suggest you fix what you have. A custom sway bar shouldn't be over $200, and you can get a kit from Ford for about $300 to switch to a rear sump. Then all you'd have to do is redo the motor mounts to get the engine down where it belongs. With the front steer, exhaust rerouting shouldn't be an issue. And because the Nova/Camaro cars are so popular, there's all sorts of parts out there, both stock and modified. If you wanted to lower the car some more, shorter wound springs are available, as are dropped spindles. In fact, even though the clip has been narrowed, if you needed to tuck the wheels in even more there are "narrow" control arms available.

Short of acquiring a new, unadulterated frame it may be the best, and most cost effective alternative to fix the existing setup.