I followed up with the dealership I got my Wrangler 4xe from and they told me that "FCA will handle it". The dealership did report the sale to FCA as, like you, I received all the Sirius notifications of Wave activation and it has an "In-Service" date which is the date I bought mine. The only thing that gave me pause/concern is that I financed my Wrangler from a personal bank (not the dealership) , so I don't remember actually providing my SSN to the dealership. I did talk to Patty at Jeep Wave and they said not to worry about any of that, as the purchase agreement would certainly provide the required proof. I even called the IRS helpline and the agent I talked to at the IRS said not to worry about it, as it is literally a brand new process and even the IRS department was not aware of "how" they would tell Sellers to communicate the sale to the IRS. The IRS Agent could not tell me the name of any form/letter that a Seller has to submit, and I am sure (cause the government is all about forms) that there will be some sort of further guidance/instructions put out there about it in the future. Ultimately I have the paperwork on my purchase that is all signed/dated. The state has the registration. When I file my 2023 Federal returns (in late Jan of 2024) I will complete the forms in accordance with IRS Guidance. Credits for New Clean Vehicles Purchased in 2023 or After | Internal Revenue Service There is also guidance given here: Federal Tax Credits for Plug-in Electric and Fuel Cell Electric Vehicles Purchased in 2023 or After which walks you through the amount and forms needed to be filed.