I've gotta say here than an EVO pickup is as far removed from a stock Ibanez pickup as an apple is from a bicycle.
There is simply no comparison (unless maybe you're playing through a JC Penny practice amp...)
First, the stock pickups on an RG270 scream like the devil. *I don't mean that in a good way, either. *The slightest little bit of feedback and they go microphonic. *Add to this the fact that they sound like garbage and you've got nothing good.
The Evolution pickups, while not my cup of tea, offer a ten-fold gain boost over those stock pickups as well as a severely increased midrange response which is easily capable of taking your face off (which is mostly what I don't like...)
*They also, just like every other DiMarzio pickup I've played, do not go microphonic when you breathe on them.
In my personal experience, the single fastest way to change the tonal character of your guitar is to change the pickups. *
This said, it's also a very personal trip to take. *Just because Steve Vai plays an Evolution, or because I feel the Steve's Special is God's gift to the six-string guitar *doesn't necessarily mean it's for you. *Start experimenting with pickups. *DiMarzio offers a 30 day exchange policy. *USE IT.