rockauto has both the upper arms oem about $145 eachOEM upper and lower control arms are showing $902 on GM Parts Direct. I went to Amazon and looked at the AC Delco Advantage, AC Delco Professional, and MOOG replacement control arms, but the reviews have me scared that they aren't built very well.
As much as I hate to let go of $1,000, if it means it'll be done right with quality parts that will last for years, I'm willing to pony up the cash.