My 2012 R56 S is currently fitted with a factory JCW tuning kit and exhaust and I'm looking to install a catless downpipe.. I know that this will cause a CEL however I've heard of some downpipes that are designed not to cause a CEL. Is there any options anyone knows of that won't throw a CEL without me having to re-tune as I already have the JCW tune?

 

ALSO if a tune is the only option, which ones in specific will work with the catless downpipe and solve the CEL problem.

 

You may be able to get away with using one of Mariokart’s downpipes..... as far as others.... doubtful. Before tuning I even tried one of those bung extensions to no avail. Rpm tune also from Mariokart will take care of the CEL and give you more power than the JCW tune.

 

You can also use a CANTool to hide the CEL. I have one for sale if interested.

 

Only DP that wont throw a CEL is stock because its catted and has O2 sensor included.
You not going to find a downpipe that's catless that wont give off a CEL and the best option is just what Grumpy said.
MarioKart Downpipe + MarioKart RPM tune to hide the CEL = Enjoyable power!!