it'll throw a code OP unless you have an ECU flash or an O2 spacer
The only downpipes that guarantee not to throw a check engine light are those that use GESI cats (Active Autowerke) or HJS cats (Fabspeed).
If a downpipe is reasonably priced, it's not using any of these two cats. :cry:
+1 :D
I'd like to see more data on that with stock power, all the data i have seen is with tuned cars.
If you have stock power data, please post them here or dm them to me, I'm more than happy to take a look
No power difference between a high flow catted downpipes and catless under these conditions
1- the cats are high quality and not restrictive
2- stock turbo
If you upgrade the turbo, the catless will make 20-30 more whp
the downpipe will throw a check engine light, if you are using an O2 simulator it might trick the ECU. It's more about the simulator than it is about the downpipe brand as you can do the same with any brand.