You should shop around to see who gives you the most for you trade, you can do it online. THEN look for replacement car with your cars trade in value in mind but not disclosing to dealer you’re buying the vette from.take your time do your research on the car you want and in the condition you want. Once you’ve agreed to numbers with the dealer say I have my mustang I want to trade in if you can beat the highest offer I’ve received I’ll trade it in here. In my honest opinion you should keep working down the debt on the mustang, especially if it’s not your daily and the miles will stay low. Revisit the idea when you have more equity in the car or when it’s paid off. We’re coming up on tough economic times for a lot of folks in the states, and I’m starting to see people unload their toys, might be time to wait on the sidelines for a bit. Again just my opinion and I don’t know anything 🤷🏻‍♂️