When it comes to comparisons on the road, I really don't care.
My XK lacks the raw white knuckled feeling that you should hang onto the wheel and buckle up as the dern thing is about to explode impression that my beat up 944 has. The 944 is far more engaging to drive.
However, my XK is FAR FAR more comfortable and less fatiguing to drive.
I think the Porsche wins in braking as its not ABS, for some reason the Jaguar, even full pedal travel, just feels castrated in stopping power.
Cornering the Jaguar is probably faster, but the Porsche will be more fun doing it.
Straight line, the XK wallops it.
But yet I own and enjoy both.
The Jaguar has a clear advantage at the old folks home when it comes to the little old ladies.