4 speed versus auto- which one?

For constant slip times, an auto trans is it.
For a faster car, I think n auto will do it.
The manuals use less power, but there is more room for error. The clutch adjustments must be dead on and shift to perfection. If you achieve this level of shifting excellance, there is potentail to be faster. You will need a slightly higher rear gear for this as well and a slightly larger/more intense cam to compete.

All this from a 4spd manual, "I love to row your my own boat kind of guy."

The biggest advantage of the auto, once set up is it can leave at the RPM you need to without a hitch or slip up. BAM! In your powerband and running with a push of a button.

This is not the case with a manual, but I'll never change.