Originally Posted by MHP
The factory powertrain engineers are restricted by many things including NVH, emissions, beancounters, legal, insurance, etc. We aren't impeded by the same regulations and have access to 100% the same maps the factory tuners do. . .
For those concerned about warranty, we calculate our own checksums (never have CELs) and BMW dealers do not have the equipment necessary to see the changes we make to your ECU file. So warranty is a non issue . . .
I'm going to trust at face-value that you are very good at what you do, and that you are thorough in your programming for the purpose of this post. However, there are a couple of minor clarifications to your claims (and I've only quoted those parts of your post pertinent to those), that I think are important for all potential tune customers to note.
1) You may not have to worry about "legal and emissions issues," because you can put language in your sales agreement like "off road use only." However, your customers will have to worry about such things if they live in a state where emissions are checked.
2) BMW dealers may not have the equipment to detect one of your tunes, but BMW "corporate" does, and they are ones who will have to approve an engine repair or replacement warranty claim, so it's not completely accurate to say, "warranty is a non issue."
Granted, a responsible tune is highly unlikely to cause an engine problem during a warranty period, but overall longevity in comparison to OEM is an unknown. However, if an engine melts down for another reason, there is a very big warranty question mark for a car with a modified ECU because the ECU is probably going to be downloaded by the dealer and sent for analysis by BMW in Germany, as a requirement before approving a warranty claim.