Here is the text of the law and my source:

I have heard from multiple LEO's that basically they will cite you, there's not much you can do about it. I've been researching the entire code for the last few weeks and I can see no direct reference to any/all non-OEM exhaust being explicitly illegal.

However there is no CARB approved exhaust other than OEM for any Subaru, so I suppose all aftermarket exhaust is in violation of CARB rules and officers may have been instructed to cite all non-OEM exhaust under that particular code section.

I know it's near impossible to get your head around this issue as I've found so much conflicting evidence but basically I think that if you're running any OEM exhaust you run the risk of getting a fix-it ticket you have to fight in CA.

Edit: This is my source for the statement "There is no CARB approved non-OEM exhaust for any Subaru"
http://www.arb.ca.gov/msprog/aftermk...es/amquery.php

Edit^2: There's an interesting post about california laws and easy reference for different violations over on this site:
http://www.scionlife.com/forums/viewtopic.php?t=165444

 

The provisions you read there put the output higher than 95db. Its in the verbiage. Key part is how there is no comma where it says so that the vehich is not in compliance with the section 21750 which reads has servicable muffler not exceeding 95db.

As LEO for the military we follow california VC so here you go.

You can put a watermelon shooter back there as long as it is intended for use as a muffler and does not exceed 95DB

Hope this helps. Of course noise level is subjective as my ears are not a DB readers so If I want to be a jerk I can ref you to be sure but I would never write A modded exhaust ticket to a subie at least unless it was a tack on or you were a total douche.

If I get popped and yes I do get stopped I ask are you writing due to noise or because its modded. Make the officer articulate if he says modded it is an immeadiate dismissal especially if you bring in the part of the VC listed above.

Hope this all helps. I would fight it.

 

Yes I am aware of the literal interpretation of the law, but it is my understanding that any violation of CARB laws are cited under section 27151 (a). Since CARB basically states any aftermarket exhaust is illegal in CA and since there is no other specific CVC violation pertaining to modified exhaust they use 27151 (a) as representation of the violation. The problem I believe lies in sloppy regulation between CARB and the CVC.

Hence my conclusion that running any aftermarket exhaust is a gamble in CA.

Edit: I don't mean to repeat myself so I won't bother posting again, but the only section of the CVC that deals with exhaust modification is section 27151 (a). Any Engine modifications that are not CARB legal are cited under section 27156 as an illegal engine modification. You are correct that they don't have any direct CVC that is specifically for them to cite you on your modified exhaust so they use the closest and closest related CVC Violation which is 27151 (a).

 

CARB has no say in CVC and officers can only cite on CVC if say you have aftermarket intake with no carb sticker you are ticketed according to the CVC for lack of CARB approved parts.