just to share about all this piggy back - that people claim cannot be detected.

It can be detected with the obd tool - all your parameters will be operating at a higher scale which means u have tampered with the car

one technique is they look at your boost value. With these piggyback - your boost will be operating at a higher level Ie original max boost 1.2 bar but post box, maybe 1.4-1.5 bar?

This can easily explain why the car has performing so much more better - do you really think they stupid? maybe close one eye but when claim for parts exp turbo, gearbox etc, they will look at your parameters and if they are off the scale, then u are screwed