Best Aftermarket Suspension Set-up

For the most part, if you aren't actually changing any suspension geometry, it doesn't really matter what kind of system you use. If the coil over setup and the torsion bar setup maintain the same hardpoints for suspension connections (control arm pivots, steering pivots, ball joint locations, etc.), the suspension is going to have very similar handling characteristics. Coil springs can give you some interesting tuning options with variable rate springs and stuff like that that torsion bars can't, but that's about the only real difference between them. So saying a coil spring suspension is better than a torsion bar suspension isn't really all that valid of an argument at all to me.

Quality of components is then the next main point of contention. If the stock stuff is limp garbage that flexes under any kind of load, then it would make sense that aftermarket systems would be "better" just in the sense that the suspension can actually do what it is designed to do as you wouldn't have compliance everywhere throwing the geometry off. However, I think most agree that the factory components are generally pretty stout pieces and if not, can be modified with limited investment to get them there (like welded lower control arms).

So the last main comparison I see between them is "feel", which is going to be subjective to everyone and somewhat driven by what your use case is. Replacing every bushing in the car with near solid stuff is going to get you closer to that 10/10ths driving experience, but at the cost of comfort and general wear and tear. I picked my upper control arms largely because I wanted something that still used compliant bushings because my car is a daily driver. Going with heim joints or delrin would likely offer an even more positive feel, but at the cost of driving more of that load back into the chassis and mounting points. There's no wrong answer here though, it all just comes down to what you want your car to do. Both systems could be made to work with either bushing setup.

I think the main thing it all boils down to is whether you want rack and pinion steering and more room for headers or other stuff under the car. No doubt rack and pinion is a very enticing upgrade. Steering boxes have come a long way, and faster ratios make them feel much more like modern cars than they did off the showroom floor, but I think it's hard to beat the feel you can get out of a rack and pinion setup. Clearance for headers is another big one, especially on the driver's side. There's a lot potentially going on over there, so not having a 3 foot long piece of steel running in your way certainly could make things easier.