To be completely honest - stock for stock, I would say the 911's. But out of my cars, the Z handles best. The setup consists of ground control coilovers, Techno Toy TC rods, control arms, and Toyo RA1 tires. The modern R180 CLSD also helps pull out of corners a lot quicker. My 911T is completely stock, and I am tempted to say it handles better than the Z with the right driver behind the wheel. Early 911's are notorious for odd handling characteristics due to the engine being so far back. The 911 has always been in a different class than the Z, so I guess it's expected. The 914 may be more comparable? But I haven't driven one, so I can't say.
On another note - the 930 Turbo is a completely different animal. It's pretty much a point and shoot car, because it has so much turbo lag. Probably why so few survived, and most were wrapped around a tree within a few years. But this is why I like it - it has its own unique charm haha.