tell me what you think about this model i made ^^

The model is very good, but 3.5k is a bit too much for a game... The 1.6k version is very beautiful, but I think you could reduce a bit the polycount... Something like 1k.

what do you think guys : i got it down to 1.6k tris count not poly :P but tris :D and got it torn in the collar
http://ismailben.crevado.com/scarf

It looks good. But the collar is too straight. I think it also has to be torn.

It will put a lot of stress on the game engine calculating every triangle. Let the textures bring your art to life! Use this high-poly mesh, take its low-poly version (before all subdivison) and bake the normals and AO to textures. Apply them to the low-poly one, and it will look exactly the same - with a lot less triangles :)

Very nice look, great job! Is it the game ready photo with baked AO and normals, or rendered screenshot from 3D software?

I like the design and textures a lot, but 3500 polygons for a single piece of cloth may be a bit too high, especially if we are talking quads (which means, really, 7K polygons in the game engine after triangulation : half to all what you'd expect for a main character and twice for a secondary one).