I noticed an air gap between the prop spinner and the engine cowling when looking at certain angle.
The spinners by the way, look like they will come of the hubs at any time. A motion like that on a real plane would torn the engines off the wings!
I already posted a few comments in this regard, but I completely agree with your statement regarding engine sounds. We will need some developer to create a sound pack for this model.
I hope with time it all gets somehow polished.