I'm assuming this will void any factory warranty that exists because of the ECU manipulation?
It is a simple coding change for the BCM (Body Control Module), not the ECM (Engine Control Module). Things like coding the key fob to open the windows is also a BCM coding change, so I think it isn't really a warranty liability. I told my dealer I made some small changes. I also turned off the DRLs, got rid of the horn honk with locking the doors with the remote, got rid of the seatbelt chime, and changed the colors on my RNS-510 system. I would still like to turn off the cornering fog light behavior and also enable fogs with high beams. I didn't know I could get rid of that until recently. I just don't like things happening automatically when I don't want them to happen. I'll turn my fogs on and off as I please, thank you very much.
Sure, if you mess up something with the coding changes, then I guess they will say forget it. I was lucky to have a very good VW friend help me. He is an expert with his VAG-COM tool, so I was not worried. You also do a scan before you change anything so hopefully you can go back to original if you have a problem.
Oh yes, my friend also lowered my TPMS threshold to 32 psi (2.2 bar). He also enabled the flashers to come on after emergency breaking (I guess that is OK for automatically happening).
I also read that some dealers may even be willing to help you. Some others, not so much.