This is my model for the Ferrari F40, one of my all time favorite cars! The model was trained on very very high resolution images, so this should work well for images above 768x768.
A few things about the model: The trigger word is FerFourty, using this will trigger the Lora. Second, all of the images were trained on red Ferrari F40's but it's still easy to make different color cars, just note what color you want it to be, and in the negative prompt section include "red car" this will basically guarantee the car turns out the color you want. Third, like with most car models, if the resolution becomes something non-square, sometimes it will want to include multiple cars, so you can also negative prompt "multiple cars" and "2cars" to help increase the odds of just having a single normal car.
Other than that, you can keep the weight wherever you see fit. I typically like it at 0.8, but depending on your base checkpoint, it might be different. POST YOUR PICS! I want to see the model used with different art styles! With your permission, I might include it in the showcase for the model!