I have GMS1 and planning to buy a mpx 3in cat back exhaust this weekend and need your help picking a dp. Which catted downpipe is least likely to set of my CEL?

 

ZZP is always a safe choice. But with anything. If you change from stock you always run the risk. You can probably upgrade to a EZ-Flash trifecta tune to eliminate it if the CEL comes up.

 

your safe bet is a get a tune for the DP, it will minimize the risk of getting a CEL.. any of the vendors on here sell great DP, but the tune will help..

 

I ran a catless 3" ZZP with the O2 sensor elbow on my GMS1 for 6 or 7 months/approx 9,000 miles and NEVER set a P0420.

 

I had the same downpipe but mine threw a code after 40 miles. So every car is different and it's hard to predict what will happen. I'm extremely happy with ZZPs product though and I planned on getting tuned anyways. This was on GMS1 also.

 

I read that the hahn catted downpipe doesnt throw codes is this true?

 

buy this
https://www.cobaltss.net/forums/part...wnpipe-289688/

 

I have a turboXS Catless on GMS1 and it doesn't throw a code so I doubt their catted will. And they have great quality! However most are pretty good

 

Hahn catted downpipe with gms1 won't throw a code I've had it for a while . Hahn also awesome product

 

Hahn, ZZP, turbo-xs all have he same style o2 elbow, which helps with air flow on the sensor, therefore not normally throwing a code. Either way, my catted turbo-xs never threw a code before i got tuned, and if you want it, just say the word....lol

 

Anyone had trouble with a Megan catless downpipe? And if I get a downpipe would I need to get a tune?