Porsche: Tires again

Put 4 new S03's on a 964 about 6K miles back.
The rears were completely shot after 5.5K. So I
looked around for tires that might give me a few
more miles than 5-6K.

Kept the two fronts (they were still in good shape)
and put 4 new Goodyear Eagle F1 GS-D3's on.
Unfortunately, the GS-D3's were not stable.
I was told they needed 25 mile in order to
break them in. But still after 25, not much
improvement.

I put the old 2 front S03's back on and
immediately there was an improvement.
Finally, put 2 new rear S03's on and
it was back normal. Of course, I got
a refund for the GS-D3's.

BUT I'm still going to face the same
problem 5K miles from now. So anyone
had better experience with tires for a 964?
It's a cab, not a turbo.

Looking for better mileage, but they still
need to stick to the ground as well as
the S03's.

Your car needs a wheel alignment.......