A quick thought:
Sliding alone might not make you faster
The conditions/corner play a huge part too.
Lets take karts for the first example; Some thoughts:
If it (track, ambient temp) is too hot and the kart is sliding (drifting ?) around anyway, going around corners might be a little faster if you anticipate (& partially cause) and guide the slide. However, if, for example, the grip levels are good; sliding it around too much might lose you time compared to what you would have done otherwise. You might feel good about sliding it around and suddenly you see a guy who's doing otherwise and going a lot faster. (Vice versa for low grip conditions)
However, there are certain corners where you can't help but drift a bit if you want to be quick and I think that should be natural. Holding a solid line there might cost you time.
Another e.g.
This week's motogp race at valencia@ The last corner. The guys were hanging the backs of their bikes out just to go around the corner quicker because that was the fastest way around. I think Stoner was faster by as much as 0.3 sec in qualifying in that one single corner due to him doing the part better than most.
As for bikes, I haven't tried sliding out too much (compared to karts where I have had many track days); but the same principles might/should apply there too.
Just a few thoughts.