I know I'm double posting here, but seeing as this is sort of a milestone in the production of the physics engine, I'll do it anyway.
I finally got the tires and axles to attach directly to the ends of the four-link bars. The whole suspension system works properly now, except for a few visual errors here and there, but they aren't all that serious. Here's a video of the suspension in action.
http://media.putfile.com/finished_suspension
Edit: I was looking around in the Game Studio help manual and found a few new settings for each object that I didn't see before. It should now be possible to select between cuboid and polygon collision detection. Cuboid is just like mtm2's detection is now - the bounding box is used, and not always the right collisions. Polygon is what I was talking about - polygons collide with other polygons.
I found a way to make smart AI, too:
-Are we about to hit something?
-If not (or we can push it), forget it and continue with the course.
-If so (and we can't push it), what angle was the face pointing, that was hit by our collision ray?
-Is it pointing towards our left, or our right?
-Now let's see what's going on there - will we hit something on one side but not the other?
-Or will we fall off a cliff if we go one way, but the other way is safe?
-If so, go the safe way.
-If not, stop and back up.
-