err...don't know why I mentioned the dual clutch on the GT500, it isn't a transaxle, but the engines are an option.
Regarding the C8, Pietz performance has done a lot of work on the C8 ECU/trans - Emelia Hartfords car. They are observing paddle shift signal and performing an ignition cut (on the piggyback), they can't affect shift timing/pressure etc, it's all locked. They were going to work with a company in Italy to "repurpose" the GCU but needed a complete C8. Instead they are building a sequential for the C8, but that doesn't help much.