I've been looking into General Grabber AT-2's since I had them on a Toyota Tacoma 4x4 years ago and I had no problems whatsoever getting around in the snow.

And since I also have aftermarket rims with a similar offset to yours, I'd been considering 255/55-18's or 255/60-18's since I'd rather keep cladding trimming to no more than I've already done. And besides, a narrower tire does better in the snow than a wider one anyway, so unless you just like a meatier "look", you're not really doing yourself any favors going with wider tires for winter use.