With engine in car:
Remove radiator and fans, easier access to front of engine.
Remove intake and exhaust manifold, if you need to replace o-ring in rear of balance shaft housings. (with 200+k these are probably a major contributor to oil leaks.) While intake is out, replace o-rings for Oil Seperator (oil filler tube).
If the oil pan is leaking, you will have to support the engine from above, and remove lower cross member. (front end alignment required after you finish)
If you remove engine:
First remove Transaxle (this alone may color your decision to work on the one in the car)
While its fairly easy to pull the torque tube back to dis-engage from engine when removing, it can be very frustrating to line it back up when you re-install.
Again, you will need to remove radiator and fans, and if going out the bottom, remove lower cross member. (remember front end alignment)
I would.... start repairs with the engine in place. If you see that more is required, then you can proceed to remove the engine.
good luck
JM