Hi Seb
Welcome to the Forum
First make sure the engine is in Tip Top condition and well serviced (don't forget Transmission and Diff) if it is then you should have no issues. I would ask how many they have done and see if you can talk to other owners
Most problems occur when ECU tuning is carried out on a mechanically sad engine and it then gets heavily used, result an engine failure with the tuning blamed. Most issues are heavy right foot is my experience
Dave