[paulca]

This always worries about ECU flash tunes. In a modern car, everything is controlled by software in the ECU. As a software developer I am thankful I do not work in the auto-motive department as the software quality controls and testing requirements are huge. Almost every line of code has to be documented, justified and defined for testing and potentially legal cases later on if they are suspected of causing death or serious injury... yes, it's that serious.

Then you hand over your car with multiple-million dollar developed and tested software to a bad street greasy tuning shop who flash it like it's an Android phone!

Scary stuff.

The downside is, if you fit aftermarket parts you might not get the full benefit from them without a flash. I believe you can have some parameters tuned more safely, but a full ECU flash sounds ... well... just dumb IMHO.

If I was Toyota/Sion I would tell you to walk.