is diet sprite as bad as diet coke?!
The only difference is that diet sprite doesn't have caffeine. But to be honest diet coke really is not bad for you. Caffeine can be healthy in moderate amounts (and it would take like 3 cans of diet coke to equal the caffeine in one coffee). Also people used to think that fake sugar used in diet sodas (aspartame) caused cancer. But it turns out that the tests were done wrong, and there's no recorded harmful effects of artificial sugar. Also people say that the citric acid is bad for you, but most sodas are much less acidic that many juices.
So basically, neither are bad for you.
"Bad" in what sense? They're pretty similar, nutrition-wise -- which is to say that neither one of them really has anything good to offer your body, aside from their water content.
i belive the majority of diet drinks use pretty much the same ingredients
No, diet coke is poison.