Alright, I'll clear this up since there are lots of opinions here
1)
Flash Tunes are the easiest to detect; If they detect it when you go to get your service at BMW, it is noted down in their system and any free mechanical related services (oil, coolant, etc.) that are under the warranty could be voided
at their discretion. It does not matter if the tune did not cause a problem. This was a deal you signed with BMW when you bought/leased the car.
2)
Chip Tunes can technically be removed before going to the dealership; however when they plug in your ECU, they can detect abnormal changes in boost pressure, oil pressure, fuel consumption, and more. They can deduct from that that you must have tuned your vehicle even though the tune is not physically there. And so, they can void your mechanical warranty
at their discretion.
3) There are some modifications, however, that can be done without voiding your warranty. Some include
lowering springs, wheel spacers, wheels, trim pieces, and miscellaneous accessories -- but no engine mods! That is an automatic red flag for BMW. Once you do any type of engine mod (downpipes, tunes, intakes, etc.), they have the power to void your mechanical warranty.
I hope that helps a bit. If you need me to cover anything else let me know!!
