Just paid 300 bucks for a PMV to fix my ABS problem at the local wrecking yard. AFTER the non-refundable payment (unless it fails within 30 days), I found the part on GMPARTSDIRECT.COM brand spankin' new for 20 bucks more. It'* kinda hard to search for a part unless you already have the part number, but it works great. The seal for the sunroof that the dealer wanted 71 bucks for was only 43 at their site.....no transportation, middle-man, dealer markup.
Always look there first for stock parts. (sorry deathrat, no commission today!)