Yes it's true. But some will work terribly.
I generally replace BTRQ file only when a new car has a problem with automatic gear shifting (e.g. sometimes new car can't shift up because of rpm limit of replaced car).
For favourite cars I create completely new BTRQ files, because in TDUPE you can set only maximum power and torque parameters. To get closer to the real behaviour of the car, you must tell the game how the car works from the initial rotation up to the redline, and the BTRQ file is responsible for that. My TDU experience tells me that the game reads quite accurately lines of power and rpm from BTRQ, but this file it's not the only source of information for the game. To set cars perfectly I was trying to find that another, but unsuccessfully.
In fact, to have a good fun BTRQ Editor is enough tool for me in terms of power & rpm settings.