That's interesting, because your car models are perfectly smooth in their curvature, unlike, say, NFS: The Run (which in itself was a very impressive-looking game in the environmental perspective), where even from a short distance you could see all the individual polygons making up the wheel wells. I never thought that the render engine made the difference in smoothness and such, I thought it was all in the model.
And I think that of the two FM4 is the most impressive, graphically and physically. I'm eagerly awaiting the arrival of FM5, or whatever else it could possibly be called.
I'm not so sure if the surface flows right everywhere, but I think there is a problem with the lines near the front wheel arches. I"ll wager a guess taht you use the polygonal method. I do love your model though.