Two friend of mine like Jag XKEs. The one in France has a beautiful V12 convertible. He's taken me out in it. My other friend had both a V12 and a 6 and let me drive both.
The V12 is a 1972 model. It is like driving a tank, in effect. (It also is missing 3rd gear, which wasn't really a problem.) The steering is wobbly, the handling is bad, the acceleration is rather tepid, were it a modern car, well, it simply isn't. I probably could outrace it on a track in a modern Civic.
Another friend did a very nice resto-mod on a 1966 Mustang. It looks great, and drives horribly. He fitted disc brakes and a new suspension system, the thing was a raw hulk when he started it. It has a modern 302 in it.