Suspension upgrades ,the best route

A torsion bar is a coil spring that has been "un-coiled". They sit low keeping the center of gravity low. The ride height is readily adjustable with regular hand tools. Yes, coil springs are cheaper, so if you choose poorly multiple times, there may be some savings. An aftermarket system like the Alterkation will provide more room for custom headers. Excellent headers for any reasonable engine choice exist that will clear the original suspension/steering at a fair if not low price.

The rear leaf springs are light, provide lateral axle location, a bit of passive "rear steer" and good traction. Any "road" type tire will clear fine.

Rack and pinion steering? Why?

Motor plate ?!? There are cheaper ways to make your water pump leak, transmit excessive vibration to the chassis, and weigh more than the factory mounts. Or, maybe not. But why?!?

Chassis stiffening? BUY THIS FIRST!!! http://store.uscartool.com/a-body-chassis-stiffening-kit.html

Heim joints suck on the street. They really do. (they extra suck on Jeeps, ask me how I know!!!)

What do you plan to actually do with the car? The basic A-body platform is really quite capable. But if, through "bright shiny object theory" you feel you need to buy some stuff that will give a Honda guy an instant orgasm, just buy...