The program that holds your cars Engine mapping is contained in an EPROM (Chip).
When you "Chip" a car you have to open the cars ECU, unplug or de-solder the EPROM. Then, read the program, modify it, program a new chip with this data then either place it in its socket, or solder it back onto the circuit board.
When you Re-map an ECU, you Read the data from the EPROM (chip) by either connecting through the cars diagnostic socket, or removing the ECU to be done remotely on the bench. Once it has been Read you can modify the file then overwrite the EPROM with the modified file. This then allows you to apply different maps where applicable and also restore the original data should you require it. The benefit obviously of this is that it means you have not changed any standard part of the car and therefore warranty is unaffected etc and insurance company’s cant see that the ECU has been physically altered.
Since we are not changing any hardware on your car, we have nothing to give a warranty on.
It is worth bearing in mind - that an EPROM by nature cannot alter the data it contains, this can only be done on a PC. If there is a change in the car following the map, it is more than likely another cause (perhaps accelerated due to the map). That said, we will do our utmost to help anyone who has a problem, including returning the car to standard for testing etc.