[Civil]

I'm turbocharging a M300 Spark and considering swapping the stock ECU with the turbo Sonic's ECU. Any idea how to approach/do this? What sensors would have to be replaced? Would this affect passing smog (relating to the ECU swap, not the turbocharger/s)?

 

[Browneye]

Your car would never pass smog. Sorry.

 

[Civil]

Your car would never pass smog. Sorry.

Do you mean because of the turbos or the ECU swap? Turbos would only make the car fail a smog test if they were making > several psi of boost at idle, or if the fabrication and/or install were faulty.

 

[Browneye]

Smog test requirements prohibit modifications unless they are licensed by your local air resources board. An aftermarket turbo and a non-standard ECU will fail it every time.
If you're building a race car then just do that - drive it on a track. This stuff doesn't belong on the public hiways.