OK OK so I actually have been working on this a little
.
Very busy but I got everything set up on my home PC after I reformatted and such.
After tracking down some old bugs I've been working on red shells:
Some comments about how things work from IRC:
AI work off simple waypoints, red shells start following the nearest forward waypoint until they get close enough to an enemy and then they change target to them instead
there can be multiple AI waypoint paths per track so the red shell could be tracking a racing line that the closest AI is not on
so you may see it alter it's course when it gets near instead of straight for the nearest target from the getgo
especially if the nearest AI is a fair way ahead of you
not sure how the official games handle them
I know they don't use waypoint systems for AI
iirc some kind of vector per tile overlay for the map, which would be too much data for this
(and later games proper pathfinding and tactical racing AI)
So there's still a few things to work out. After this I think all the other powerups are pretty straightforward.