I heard the rumour that the Dutch importer ask lexus (but Europe is small for them and Japanese firms tend to be deaf for minorities) to have all 220D's fitted with the sport gearbox (good action since imho the normal one doesn't match the engine at all).
Since I have loads of experience with OBD tuning (Revo/Jabba/Amd) on VAG products I can say I would only go for this option and never opt for piggyback.....
The best remaps only adapt centain files and leave all the safety files intact, in this way damage to the motor is almost impossible.
See it this way, Vag turbo motors that have a good remap will go into limp mode when pushed over the limits, badly tuned cars will just go on untill they blow/suffer an early dead.....