If you want a modern car just buy a modern car. There is no easy solution for re-engineering an old car into a new car. Most of the aftermarket kits for Mopars are designed to increase header clearance for drag racing, they are not designed to provide a modern handling experience. The only setup that I know of that has the capability of providing a modern feel would be a full frame conversion. But that is a huge job and there are only a few shops in the country that could pull it off correctly and the cost would be enormous. So back to my first point, if you want a modern car just go buy one. If you want a classic car that rides and handles better than it did when new then that can be accomplished but it won't have rack and pinion or ABS or airbags, etc.