thats what all dealers do the more they replace the more money they get. as far as the car, i would think its not something that goes frequently ive never heard of or had one go so i would think getting one in a yard would be alright. if its above your confidence level there are always decent local shops that would know what they are doing and charge 1/3 to 1/2 what the dealer charges. just go in and see if they sound like they know whats up, sound like they have decent scanners and keep up the shop.
1998 Bonneville SSE
2007 Monte Carlo LT-KYB, Clarion, Polk audio, Kicker
1999 Yukon SLE-KYB, Air lift, Reese dual-cam, Tekonsha
1987 Firebird-355/th400-nothing stock