well it's definately not going to give you more understeer, thats for sure
It might oversteer on you more because you got so much more power, but as for how much the weight difference is/how it'll affect driving i can't say.
But i have heard of people running them in autox's and stuff. Also remember that if you are building it up for autox then you can strip some weight off the car to help a little, and you probably don't even have a rear sway bar do you?