RE-11's mounted, but WTF?

[FastJew]

So I decided to replace just the rears on my sport package with the RE-11 285/35/r19's. My plan was to let the stock fronts (which still have 50% tread) wear a little more before dropping the rest of the cash to replace them in the next few months.

Unfortuantely my car now feels extremely twitchy and unsettled in corners (almost dangerous over 80). I mean I was expected some adverse handling with the new tires in back and old in the front, but I figured it would just push like crazy...no big deal.

Is this what should be expected with this setup? Seems like rear end of the car moves around way too much. This doesn't seem like it would be the case with so many guys running these tires on here...

Any input would be greatly appreciated...other than telling me to quit being a cheap a$$