I just put my new ones on that I got from this guy... http://www.wheeladapter.com/wheel_spacers.php
I bought the hub-centric only spacers and they didn't affect the balance at all. My only complaint was that the holes are cut to be a very tight fit on the studs. I drilled mine out a little, otherwise I doubt I would be able to get them back off after I put them on. (I only use mine during the summer) The spacers don't change the alignment, so you should be okay. My truck handles better, gets better MPG's with my summer wheels/tires with the spacers, but that's not due to the spacers, but more the wheel/tire setup. You won't even know the spacers are there. I wouldn't go any bigger than 1/2" though. I have been considering getting longer studs, just to be safe.