A body sports car handling

For the rear I would get the longest shackles you can get. Like those redneck ones people used to have in the 70's, combine those with 2 slant 6 leaf spring pack. You probably want to break the clamps off them. Next make certain you bang on your ball joints good with a 8 lbs hammer before installing them. Also you want to soak all the bushings in paint stripper over night, than install them loosely. Sway bars are extra weight, same with things like seat belts, so toss that junk. Install everything, except what you don't install, and use a lot of Armour All on your seats. This way it feels like your going like a bat outta hell when you drive, but actually you be within the speed limit.
Sorry dude, sounds like you need a size up from stock on the sway bar front, and rear, and a rebuild with some poly graphite bushings, and that car will come to life. Ferrari used to use torsion bars too, it'll be fine.