Here's a G3 ROM ported to the G2 (all variants) by OptimusRs.
Xda thread for OptimusG3 ROM:
[ROM][PORT][All Variants] -=- OptimusG3 Rom V1.0 -=- - xda-developers
Follow the instructions in Xda thread.
Xda thread for OptimusG3 ROM:
[ROM][PORT][All Variants] -=- OptimusG3 Rom V1.0 -=- - xda-developers
Follow the instructions in Xda thread.