First thing to do is look and see if the track bars are still installed, if so pull them out and junk them. Next step would be to insure your tire pressures arnt crazy high. After that take a look at your spring and shackle bushings check them for condition and check that the torque on the bolts is within spec. Over torqued bolts can impede spring and shackle movement. Body mount bushings probable wont cause issues like you describe, but badly worn motor and/or trans mounts might.
Here's a pretty nice exhaust manifold replacement walk through.
Also in the future you will probably get better results in you post in the YJ specific section for stuff like this.