My wife took our '89 truck for a smog check. They had her wait inside, then told her that it failed for visible smoke, and that they would call her with an estimate for repair.
The next day, they called and quoted us $800 for the part and 12 hours of labor. I called my usual mechanic (Aamco on Valley View), who told me it was an outrageous quote. They asked me to pick up the part at Autozone (cost of $8), and bring the truck in to their shop. I did so, and the mechanic (sadly the name escapes me), showed me how to install in, which I did in roughly 1 min. The kicker? No visible smoke.
Don't take your car here unless you want to be lied to. They literally tried to swindle me for over $700.