BMW restoration project

[GRiiM]

There are a few areas of the mesh that could've done with more tries added in as well as chamfering to make edges appear smoother, don't be afraid of a few more hundred if not thousand tris, they won't hurt anything and you should be able to preserve the current UVs. The gear stick needs a smoothing group applied to it as well.
Also please add alpha channels for the exterior paint job so that mechanics can colour it without looking like a hideous mess.
Overall though it's a very nice improvement over the old model

edit: Looking closer, there are quite a few areas that desperately need smoothing groups - seats, wing mirrors, dashboard etc. Go in and fix these and it should look much better!
edit 2: The left side floor mat needs it's UV mapping mirrored, the 'BMW' is backwards but that's just nit picking.

Yeah I know there are lots of issues, as for the alpha channel a majority of the interior and exterior textures are on the same file, so doing that would also color the inside. I'm really not in the mood to redo the UV maps for the entire interior, especially the piping and rollcage. 

I'm also not doing any 3D edits to the model since I really don't want to break anything at this point. I just spent the past 3 hours working on correcting the rotating collision model that Wormwall loves to pull on me and had to comment out an $hbox that I hope is unneeded at this point since it was preventing me from compiling the model. 

This is why I hate vehicles in Gmod, lol

Smoothing groups will not affect the model mesh so the collisions and UVs won't be affected. The collision model would be primarily for the exterior, you should still be able to add tris / chamfer objects inside of the car without the collision model being changed (though I haven't personally tried this) and Max has a checkbox in the 'Edit Poly' modifier to preserve UVs which should work fine. It can't hurt to try, if it doesn't work then you always have a save point of it's current state. 
The re-colourable texture could be done by having a texture skin with the car exterior colour set to white, then in the alpha channel just black everything out except the white exterior paint.