I'd taken my 2 cars to this place the last 3 years for the DMV registration smog check. The people there are friendly and helpful. One of my cars had failed test, and Ray the main guy there took the time to point out that all it needed was to replace a hose. Sure enough, after having my mechanic replaced the hose, the car passed the re-test. This had no doubt saved us the cost of labor to have our mechanics do their own diagnostic. \r
With a coupon, they charge about $50, plus the certificate fee. They do not charge the extra 2 bucks for EFT that some smog centers do. I suspect if you ask, you don't really need to show them a coupon to get the discount. There are other smog test-only centers that advertise for a slightly lower price. I prefer to take mine here because of their good services.