My new kitty has been stinky too. I think it is a combo of the new environment (stress) and the switch to new (premium) food, which is richer. I also noticed that she is more stinky with certain "flavors" - especially beef, so I am not giving her anything right now except chicken and a little fish. It is too early to tell, but her system might have trouble with certain things like beef or grains. I am watching carefully and keeping a food diary on her in case it doesn't clear up on its own and I take her to the vet.
I heard it will go away in a a couple weeks when she settles down and her system adjusts to all the changes. Like your kitty, she is active, drinking her water, sleeping fine, looks bright eyed and has a shiny coat. She doesn't seem to be bothered by loose stools or bloating.
I am not too worried, just anxious that the smell reduces SOON. It is truly unbelievable. I do volunteer work in a cat shelter and all those cats don't put out anything that smells like this. Whoa!!