I hope you have a youtube channel. I learnt more about MOI3D and car modeling in your post then all the stuff I read & watched elsewhere.

Can I ask what renderer do you use?

I use e-onsoftware's Vue or DAZ 3D's Iray. I also use 3DCoat's native renderer.

However since all three apps can not import .3dm, I must export from MOI3D as an obj which often gives me very bad topology (and I tried alot of settings)and causing issues with uv mapping and texturing in 3D Coat.

3DC's auto retopo feature gives me bad topology and I hate manual retopologyzing in 3D Coat. It's like modeling the object twice.

Cheers & many thanks