Best bang for the buck?

The main thing that will lower the "boat" feel is stiffer torsion bars and/or less weight on the front end. If your car was a factory AC V-8 car, it should have about the thickest factory bars available (0.870" or 0.890"D, I forget). Many like 1"D after-market T-bars ~$200. You can lower front-end weight w/ aluminum (radiator, heads, intake). Switching from power to manual steering might shave 50 lbs. From power to manual brakes maybe 20 lbs.

If you change the T-bars, be prepared to change the lower bushings. Real cheap ($11 ea), but you need a press or rig up pipes and threaded rod to get them out. There is a sticky on that.

I think sway bars and frame rails would mainly be felt on twisty roads, not much in normal freeway driving. Shocks might be a bit over-rated (and over-priced). If you push down on a corner and it springs up once and oscillations damp quickly, the shocks are doing their job. Now if driving off-road or on gravel roads, shocks become critical, but most A's aren't driven like that.