It will still throw a CEL unless you tune it out. I am running a similar brand catted downpipe from MXP, and would still get a CEL every 100-200 miles. There are a few catted DPs that dont get a CEL, but they are usually much more expensive.
I was also getting some random codes with my catted DP prior to doing a tune. jb4 does not turn off the o2 codes, so you would need to do an ECU tune and have those codes tuned out.
first spoiler had a defect... appeared to be an issue getting a chip during shipping. Bought it from Titan and they were helpful and swapped it out for another one. Zero blemishes, but I did notice that the right side corner does not like to sit 100% flush. Other than that, im happy overall...
if you want to save a few bucks you can also try the vLinker MC+. It was a little cheaper and worked fine with bimmercode. I would also check on either of these if there are any other apps that you might want and see if the adapter is supported.
I went with the MXP catted downpipe and ended up popping a CEL. I was never able to confirm the code since it magically cleared itself after a weekend, but my biggest pet peeve is that it still has an exhaust smell even though it’s “catted”
otherwise, I’m happy with it.
Personally I’m probably going Ecutek, but I talked to a few m340 owners over the weekend and they really like the MG Flasher platform. Never heard of it being used on the a90, but it seems to be popular on some of the bimmer groups