Please refer to http://www.allpar.com/fix/airshocks.html and http://www.allpar.com/fix/airshocks2.html to learn about your options when deciding what to do with the air ride suspension. You can also purchase a conversion kit at http://www.strutmasters.com/chrysler/index.htm.
I recently rescued a '91 Mark Cross edition with deflated air ride suspension. I chose to take it to an independent shop, and asked the mechanic to replace the system with conventional struts, coils and shocks. With the proper tools and skill, this can be done by a backyard mechanic as well. The front is much more complicated than the rear. The cost depends on whether you can locate a donor car and use its parts. The parts are common to many Chrysler models, and you have options as described in the pages mentioned above. I am quite pleased with the results, and I do not perceive any loss due to the absence of load leveling when taking curves at high speed.
-- David
'91 K-Imperial
-- you know your car is cool when your 17-year-old daughter wants to drive it