I have researched and researched about what performance upgrades I can do to my car (1999 Lexus GS300) and still pass smog in CA, but the laws are so strict. Not sound wise, or cosmetics, but just some extra HP or Torque. I have a K&N air filter and H&R springs, that is about it. Looking for brakes also. Any suggestions?

 

So adding a turbo with low boost or going with a GTE swap will not pass smog?

 

I would most likely (90%) not pass with a turbo, unless I go to a shady place that runs a shop Honda Civic smog as mine. Maybe low boost? Plus, most smog places in CA have a visual inspection before the emissions test, and that would not pass if I have a turbo on there. Even if I were to get a turbo with low boost, any suggestions?

 

The actual K&N air intake kit is 50 state legal but you will probably have to buy new to get the carb sticker because most people lose these. I would maybe change the rear section of the mufflers to a bolt on kit so you can take it off/on whenever for inspection. Just don't expect more power, there might be 10 that get to the wheels.