How many modified (assuming CARB compliant parts) are going to run smooth enough to be drivable? Going to have to complete drive cycles too before cruising to the smog station. Good luck
What if there are passengers in the vehicle? Any back seat passenger may become a potentially lethal projectile to the driver or front seat passenger. The driver could be catapulted sideways or even backwards with lethal consequences.
Yes, and by the logic of "its my private property so the government shouldn't be involved" that scenario is a consequence of my personal choice and risk. It doesn't involve anybody else on the roads. Plus, in any accident, the driver can lose control, making the vehicle itself a projectile. So based on this alone we can't use the "big bad government can't tell me what to in the private space of my car" arguments. In other words, I agree with the seat belt laws and understand why this will pass too. These are public roads and driving on them is a privilege not a right.
Interestingly enough - there are many times when a properly performance tuned vehicle will actually be more efficient and have no adverse tailpipe emissions and, in a few cases, I have actually seen BETTER tailpipe admissions with a solid tune. I hope this stays in California but we all know it will eventually trickle to other states.