Has anybody ever installed a 2G engine in a 1G?

Not so far. This modification is not likely to be popular, since the 2G engine is more expensive than a 1G engine. Also, it has other characteristics (such as a smaller stock turbocharger) that may make it unattractive to 1G owners.

Anyone wishing to attempt this swap should be warned that it is not trivial. Although many of the mechanical attachments will work correctly, some 2G engine sensors operate differently than 1G sensors, making it virtually impossible to use without an ECU and wiring swap as well.