[__gorr]

I have a 2023 540i with a muffler and resonator delete. I am looking into getting a tune from either JB4, BM3, RK, and Dinan.

I want to not touch the cats or get any downpipes. So, which option is the best for a muffler/res delete + tune?

Let me know which one to go with to get decent power, smoothness, best bang for the buck and which one is overall the best one.

Also, Is it easy to take the tune off with no trace (For taking to the dealer).

[mike@x-ph.com]

You cannot do bootmod3 or any flash tune unless you will ship your DME to Russia to unlock it.

Unless you are after a big build or 100% E85, it's not worth it, in my opinion.

Your best option is piggyback, the Jb4, the most advanced tuner on the market, and offers the most power and features.

[WretchedRefuse]

I would also caution that, regardless of how you tune it, there is no such thing as removing the tune without a trace. Even if you remove a JB4 before taking to the dealer, the engine can still record over-boost conditions and the dealer can read that and deny warranty coverage. Maybe you will get lucky but the advice is always to assume that your warranty is void if you tune the engine.

[mike@x-ph.com]

Originally Posted by WretchedRefuse

I would also caution that, regardless of how you tune it, there is no such thing as removing the tune without a trace. Even if you remove a JB4 before taking to the dealer, the engine can still record over-boost conditions and the dealer can read that and deny warranty coverage. Maybe you will get lucky but the advice is always to assume that your warranty is void if you tune the engine.

With all due respect, that's not true.

Your warranty is not void if you tune your car, even if you leave the tune on. All my cars are leased and fully built, never had any issues with the warranty or at the end of my lease.

The Dealership can only refuse a job if your mod caused damage and not just because they don't like your tune.

And, there is no proof that the dealership can still know the car is tuned after the tune has been removed.

All the data, as proven by hundreds of thousands of tuned cars over the last 15 years with Turbo BMW, show otherwise. the tune is either undetectable or detectable but the dealership doesn't care. Either way, the warranty is intact.

If dealerships flagged cars after the users removed their tuned, these forums would be filled with angry customers.

But that's not the case, these scare tactics were used back in 2007, and 15 years later, this is no longer up for debate.

[WretchedRefuse]

Originally Posted by mike@x-ph.com

With all due respect, that's not true.
...

Thanks, I hope I stand corrected on this, although I was just repeating what others have posted. Is the same true of a DME flash tune, if the tune is removed before taking into the dealer?

[mike@x-ph.com]

Originally Posted by Wretche; Ifuse

Thanks, I hope I stand corrected on this, although I was just repeating what others have posted. Is the same true of a DME flash tune, if the tune is removed before taking into the dealer?

Its impossible to say what's detected and what's not, but from all the data we have, the question is not necessarily whether they can catch it but whether they care.

And from what we know, unless your aftermarket upgrade breaks a car component, the dealership does not care.

So if your upgrade causes damage, the dealership will not fix it for free, which is fair, in my opinion.