i thining of getting underpulley and ECU upgrade, will this make me failed the CA smog check?

 

I dont think it should be a problem. What year is your car? If its an 03, you got 2 more years before you need a smog check.

 

i didnt know smog check is due in 5 years on new car. ya, i hope i can upgrade to a CLS or S class in 2 years! haha
but then the new owner will blame me for cant pass the smog check..

 

Yeah, new cars dont require a smog check for registration for the first 6 years, unless you are doing a transfer of ownership, then its first 4 years. But I wouldnt worry about it. Take it in for the smog, dont pu stickers or anything under the hood to give it away that you have pulleys or an ECU upgrade, dont tell the technician anything and you should be fine.