The reason for the swap to coils. I had a chance to drive a buddy’s car with coils on an auto cross course. It was the best handing a body I have ever driven. It’s a daily driver and has excellent street manners. Plus I hate the headers on my car. I’ll be using a power rack and pinion as well.
While I don't doubt your buddy's car handles well, the fastest, best handling Mopars still run torsion bars. With the aftermarket parts currently available, you can run torsion bars and have a car that handles just as well or better than one with coil overs. There's nothing magical about coil overs, they're just a spring and a shock. Run the proper wheel rates with the right shocks and torsion bars can do the same. And the Mustang II design used by most of the coil over conversions is not inherently better than the design of the torsion bar suspension on these cars. With the proper aftermarket parts you can get better geometry with the Mopar torsion bars. And the chassis carries the suspension loads where it was designed to.
It's true, header clearance isn't great, but you can save thousands running a modified torsion bar suspension compared to a full coil over conversion. More than enough to buy a set of Doug's or TTI's. And a rack and pinion really has to come with a full conversion. Although frankly, they don't improve actual handling performance, just change the feel a little. A new Borgeson box solves all the other issues from running Mopar power steering.
Make your choices and spend your money, but if handling performance is the goal it can be achieved just as well with torsion bars, for less money, than a coil over conversion. Plenty of evidence of that too...