Looks like you posted about this last month as well...
If you’re building a car for street use and even just decent handling the /6 torsion bars and KYB’s belong in the trash and not on the car.
For the rest of it you can look at this post. Keep in mind if road courses are something you’re going to do you’ll probably want larger than the 1.03” bars I list for basic street use. And the chassis stiffening will need to be done as well, because high speed road courses will put a lot of load on the chassis. I would put everything on this list ahead of a 4-link. Not because 4-links don’t work, but because you’ll need everything else to take advantage of them. You can do really well , even on road courses, just with leaf springs. And they’re a ton less expensive than a proper 4 link install
