[Strange behaviour in tight turns]

Sounds like a bad CV joint. They are inside of the rubber boots that are at the ends of your axles. You typically check if they are good by making sharp turns. If they are OK the turns should be as smooth as when driving straight. If bad they do something like what you mentioned.

[96 EJ25 Retune to run on 89????]

Have you tried running on 87 octane? My 96 OBW with 2.5 runs on 87 octane with no pinging. I live on a long, steep hill and have not had pinging yet using 87 octane. Also checked gas mileage between 87 and 91 octane and no difference.

[Slipping transmission]

I changed the fluid and filter in my 96 OB automatic transmission and now it slips when shifting from 1st to 2nd. Once it catches in 2nd every thing is OK. All the other shifting seems normal and every thing was fine before I changed the fluid.

I had to move a tube out of the way to remove my filter. Could I have put this tube back in wrong and caused this? Any help would be appreciated.