Uh-oh...
Is it 'supposed' to look that good???
That's odd since the A-1 was just a simple modification of the Microsoft model by clipping the wings. The best way to keep the framerates within reason is to make 5-6 LOD's.
The skin resolution doesn't make a bit of difference, comparing a Spitfire IX with a 1024 skin to the same model with a 2048 skin gives the very same 54-55 fps with both. However, comparing a Ju 88C-6 (Ted's work) to the Ju 88A-1 gives respective figures of 62 fps and 44 fps, both with 2048 skins, so there's definitely something in the model. Absolutely no idea what, though.