Autogas for the Stinger

Greetings dear car community, so I got a Stinger 3.3 T-GDI and would like to retrofit a gas system now. I have made a request with 3 suppliers and with Zavoli, as well as with Prins no conversion for the Stinger is offered. (I forgot about the third one) I know many of you will want to start a discussion about gas systems now. Before we start, I would like to know if someone has already upgraded? If yes, which system, where, how much cost?