Subaru Impreza WRX 1995

I went to the track couple of days ago. Car was handling so
badly while cornering that I could not believe that it is 4-wheel
drive anymore. It was heavily oversteering. Since I switched to
Kumho Ecsta SPT tires it was not handling too well, but this time
it was much worse. For some strange reason it was very difficult
to compensate and correct once rear start running off. Same day
I did geometry and wheel balancing, and on the way to the track
it felt sort of OK. I drove this track before, and to my best
recollection I could take same corners at much higher speed.
Tires temperature and pressure seemed to be OK. Just started
with some easy laps. She went to eat grass twice, kissed off
concrete barrier, and went back home on the slide car. Clearly
my error in judgment. Just want to get better insight what could
cause such a poor handling. Any ideas ?

Note on tires. It was first Kumho I ever used. I never like my
experience with that particular model. On other tires it was quite
clear when you are at the end of the grip, on Kumho it was more
like "Um... I think I have gone too far".

Another thing, on the way to the track at one point I've heard
sharp loud noise, like rubbing a stick on a picket fence coming
from under the car. It continued until I stopped. I checked around,
but could find nothing, and when started driving again everything
was back to normal. Is it possible that it was an indication of some
drivetrain problem ?