Not sure what the stock wheel rate on the transverse bars is to be able to calculate an improvement. No doubt they could use some help, but what is the price of improvement as these bars are not cheap.

In my experience, better shocks is a challenge. I converted my last Mopar F body to use 1st gen GM F body shocks. That opened up a whole new world of selection.

Agree replacing the subframe mounts with solids is a big improvement. I also recall a magazine article series where they added strut rods to an FJM system to help reduce load deflection. A big problem with the transverse bars is they do both spring duty and location duty. With the big rubber bushings they have, location can be compromised under load which creates weird alignment angles. The struts prevented this from occuring.