Not sure what you mean by "inside scoop" - all the regulations and requirements are published on the DMV website.
There are a few threads on the forum where I posted more extensively about some details, but there's not really much mystery here.
sadly, due to the strict guidelines of the DMV and misc tests, it has sent many an vehicle, to a timely demise..or at least SOLD outside California....I obtained my Fiero this way...couldn't pass ...but was good in just about any other state....
As a guy with a dozen vehicles to my name at any moment in time, the vast majority of which are older and several of which are pretty highly modified, I will say authoritatively people who can't get their cars to pass California emissions are not very good at cars or pretty lazy or both. The smog tests are feedback-driven - the emissions targets are based on actual test results. The reason they provide the "AVE" number in the test is so that you can see how your car compares to other identical vehicles. If you can't hit the AVE number, you've missed a maintenance interval or used too many no-name parts. My '87 GT passes *easily* - it's not even close.