So this car is 2,312,448 triangles (809,216 for the body and 375,808 for each wheel). For reference, that is about 200,000 more triangles than the first 4 levels of the game combined. To clarify the significance of this, levels in this game are about 8 to 10 regions a piece with only about 3 of them loaded at the same time.
It's way higher detail than it needs to be for this or any game, though as you didn't make the model I'm not sure if you can do anything about that.
Also you included a .bak file with the in-game model and the car shop model of the car which doubles the file size of the Mod for no good reason, you can exclude them from the .lmlm file by adding the following line to your Mod's Meta.ini's Compile section:
ExcludedFileName=*.bak
When a mod is decompilable, it includes all files by default so if you want to leave anything out you have to specify it in that way. The .bak files don't serve a purpose to anyone so it's good to leave them out even if it's decompilable.
Also if you want to reduce the file size further, you can create a CustomFiles.ini in your Mod's root folder and add the following lines to it:
[PathRedirections] art\\frontend\\dynaload\\cars\\audi_r8.p3d=art\\cars\\audi_r8.p3d
This will redirect the car shop model to the in-game model for the car which should work the same in this case since as far as I can tell these 2 files are the same. If you decide to do this, you can delete the car shop model since it's no longer needed.