The bottom line, nothing (new or not) will increase the handling or performance using 60's technology.
Here I somewhat disagree. A spring is a spring is a spring. The coil springs under your Alterkation are similar to a coil spring put under a car in the 1930s. Since when cars were first built to now, there are only four methods of supporting them; leaf, coil, torsion, or air.
What has changed is our understanding of that spring and its interactions with a variety of different forces and how best to utilize it within its range of motion to optimize that force.
This is not a slam of the Alterk, it is a quality piece that is very effective and creates a lot of room with improved suspension motion. If you understand what was changed in it from stock and why, then you can understand how to create the same improvement in the stock based components. Ultimately, however, it may cost as much to achieve the same results using stock layouts as what you get in aftermarket layouts and you won't get as much space nor ease of spring changes that comes with the nifty coil over arrangement.
In your case for your buck and your time, the Alterk was the best solution. For many others this same logic applies. For some of us, it does not. Additionally, some of us can build a stock based system that will perform on par to an Alterk. It all depends on how you want to spend the time, effort, and money and what you are trying to accomplish with those variables and within what rule set.
