I've got a BMW M340i and I'm debating between a piggyback

Hello everyone. I've got a BMW M340i and I'm debating between a piggyback module and a proper ECU remap. The piggyback is easy to remove before dealer visits, but I've heard a real remap is smoother and safer if done right. I don't want to void anything major or risk the engine. For those who've done engine remaps here, what was your experience, and how do you know the tuner actually knows what they're doing? The car is about three years old and has been serviced at the dealer so far. I'd rather do this once and do it right than go back and forth.

I went through the same debate with my 540i. In the end I did a proper engine chip tuning deiz-garage.ae/chip-tuning/ instead of a piggyback, mainly because the throttle response and power delivery felt far more natural. What convinced me the tuner knew their stuff: they used BMW's own diagnostic system first to check the car's health, then calibrated on a dyno with before and after runs, and the guy doing the calibration had something like twenty years in the game. They also explained what they changed and why. On warranty, be realistic, a remap can affect it, so ask yourself honestly whether that matters for your car. Mine was out of warranty anyway. Driving it for over a year now, no issues.