Stay away from the wheel spacers... not because they're dangerous (because I don't think they are) but because none of the tire shops or 4x4 shops in town want to touch them. Most won't even bolt your tire/wheel up to them, even if you have the spacers already installed.
America's tires wouldn't even balance/rotate my tires when I had a set of Spidertrax spacers on my Jeep with the stock tires. I had to take the tires off, put them in the truck, go to the store to get them balanced, go home and put them back on myself. After doing this twice, I bought a new set of wheels. Should have done that in the first place.
Precision 4x4, and Rob's Offroad in Clackamas wouldn't touch them either. That's when I stopped doing business with those 2 shops... they wouldn't work with wheel spacers, but they'd sure as hell sell them to you.

The only place that i know of that will install and maintian your wheel spacers is 4wheelparts in portland. I belive with the economy dumping the way it did profit out weights liability.