[Mikey29]

I have a 21' 540iX and recently got the M performance exhaust for it (pretty underwhelming for the price.) thinking of making it more aggressive, does anyone know if the VRSF catted downpipes would throw a engine light ? And would I also need 2 of them?

[Mikej0h]

With the CEL it's a hit or miss, but count in you most likely will get it.
After you change the downpipe, you probably want to tune your engine to also leverage the performance gain. Bootmod3 is one of those, and allows you to also remove certain CELs when they pop-up.

Oh, and you need one downpipe for the 540i.

[iiwilsonii]

I have read that VRSF, ER, CTS catted downpipes will most likely throw CELs. I have a CG DS-1 catted downpipe and the CEL is on and off. I’m assuming you won’t be tuning your car as I don’t think the ‘21 models can be tuned without a bench unlock. So if you are looking for no CEL you should look into the Active Autowerke downpipe which uses an EPA approved cat that guarantees no CEL

[DBO]

I've been running the VRSF catted pipe for over 18 months and haven't had a single CEL.

[mike@x-ph.com]

If you run the VRSF without a tune to hide the check engine light, it will pop up.

If you do not want a check engine light, check out the active autowerke downpipe with GESI cats

[True Story]

Ive had my Acetive Autowerke catted DP that I bought from Mike@x-ph.com and have been very happy with the results. No CEL in 2 months so far with JB4 and Remus catback.

[mike@x-ph.com]

Originally Posted by True Story

Ive had my Acetive Autowerke catted DP that I bought from Mike@x-ph.com and have been very happy with the results. No CEL in 2 months so far with JB4 and Remus catback.

[DealBMW]

That is correct. I have an ER catted dp and the CEL comes on every couple hundred miles, then goes away, so it's 50/50 pretty much on and off. Next time I would either go with a catless option for better sound and performance or AA for no CEL.

[BWilson263]

I have Evolution Recewerks catted downpipe with BM3 tune for about 2-3 months and no CEL yet.

[Joe-BMW33]

Downpipes are a can of worms. If you are okay trouble shooting them, having the car tuned and retuned (bench flash) and dealing with uncertainty with state inspections or warrantees, it is your car. Personally, I read so many posts about CEL's, malfunction check controls, etc. that it is not worth the extra HP, sound or gas smell. At least you are thinking catted though.