Just one thing. If you replace your cat and aren't running an AIR pump, make SURE it's a non-aerobic cat from a fuel injected Jeep XJ or something. Otherwise you will lose power in short order and the emissions will be through the roof!
Replace the aircleaner with one that A: doesn't have the pulse air ports sticking out, and B: doesn't have the shut down flap that's supposed to close after you turn the car off. They tend to fail after 20+ years and close while driving, causing single digit fuel economy and running problems.