You ship them a worn-out PS gear box (fits in a 5lb bucket), they rebuild it and send it back. Which is why you either plan to get a second gearbox solely for the rebuild, or have your vehicle out of commission for a little while. I’m not sure about the current price - it was $150, then it was...
If you can pass inspection the way it is, and it’s running well, I would leave it.
Most people de-smog because the stock emissions system is a complicated clusterf**k of plastic valves and vacuum lines that stop working in stages, which can leave you chasing problems for years on end as the...