I want to share my experience hunting tyres for my 1985 XJS. 215 70R 15 is difficult enough to find, much less a speed rated version. I ended up having a set of four MAXXIS MA-P1's shipped in. They are H rated (130 mph). The price was reasonable at $90 each. The ride is much more responsive although stiffer and a bit noisy. The problem so far has been an acceptable balancing. Three different shops have attempted but still not perfect. But all in all, much better than the Goodyears I replaced.
David
Albuquerque NM
1985 XJS