Best Aftermarket Suspension Set-up

Not a great example, torsion bars can't work with a live front axle and anything is better than front leaf springs if ride and handing matter. Look at late-model GM trucks and Dakotas, they used torsion bars for packaging reasons so there could be space for the CV shafts for IFS and 4x4. Other makes (Toyota for example) use coilovers on their 4x4 trucks but it's designed in a way to make room for the CV shafts and is arguably a bit more complex/expensive.

By themselves torsion bars aren't much better than coil springs, it's just that the original Chrysler front suspension design was very good in terms of geometry and dynamics especially compared to GM and Ford cars of the same era. It can be upgraded in stages and comes very close to modern cars in terms of handling with the right mods.

If you need extra room for exhaust and oil pan, want to set the engine further back, be able to use rack-and-pinion steering etc. then coilover is the way to go.
Funny story.
Earlier, about 7 months ago I was talking to a co-worker about cars and such. He being a hardcore chevy guy (but one of those paper-pusher, never touched a wrench or changed his own oil type).
He asked some questions about my car and when the subject came about me updating my torsion bars and stuff, he didn't quite understand that how they functioned.
So I gave him the basic low-down on how they work, his comment was like that "Sounds like old technology and that the handling and ride would be horrible."
I then said "How does your truck handle and ride?" He said great, I then had to break the news, told him his 2022 Silverado (2500HD Duramax to be exact) is actually a torsion bar suspension as well...
His response was like "Oh... shows what I know." It's fair I told him, I'm a big gearhead and he's not. He's big into sailboats, so I'll be picking his brains about that since I'm curious.