In Regards To Your Meshes

I can’t help but notice that all of your meshes, whether they are in LOD0 or LOD3, are comprised of triangles…It’s best to avoid creating meshes in triangles. Perhaps your performance hits are because your meshes are not made up in quad polygons.
You should research this further. Triangles = bad…

A quad is two triangles, just the software hides it for easy manipulation of the mesh.

Unity 3D (the engine they use) like most other game engines don’t render quads, they only render triangles. When importing a quad based mesh in to unity it will ether fail or convert it to a triangle based mesh.

Triangles are only bad for animations/modifiers sins they don’t deform/divide well, thats where the “triangles = bad” thingy comes from in modeling community and related guides … triangles have little to no impact on rendering or animation performance and are in fact the only option in most real time rendering engines for a reason. (as mentioned before some engines and modeling tools do hide triangles by pretending that they render a quad)

I don’t think you appreciate how great triangles are

http://cinnamongirl21.files.wordpress.com/2011/07/bridge.jpg

If you’re ever looked at any structures ever (especially bridges) you’ll know they’re* the shit.*

http://www.artinaid.com/wp-content/uploads/2013/03/Puente-con-estructura-triangular.jpg

Why? Because triangles are strong as fuck in structure.

See those other, shitty, inferior shapes? They’d bend and break because they’re shitty and don’t support their other joints to stay rigid.

Triangles are also awesome in graphics, because guess what?
Quads are really hard to render. Here’s a far smarter person (than I) explaining why quads are gross and never deserve to be considered for any serious engine: http://stackoverflow.com/questions/6100528/why-are-there-always-triangles-used-in-a-3d-engine. If you’re too lazy to read it, then consider how a triangle is always flat, and all its points are always in the same ‘plane’ (which in graphics makes them way easier to manage than a quad, which could have 3 points on the same plane but a fourth on a different plane, AKA not being ‘flat’). Also, triangles can make up ANY shape (given enough triangles), but not every shape can make a triangle (which makes shit complicated when you want to make a triangle).