Noticable shimmering you see is mainly there because of compression.
Of course, the shimmering also exists in the game, but it not a problem of an engine, but the problem of TV sets.
As the PD is making GT engine code as a doubled vertical resolution all since GT3, some of the lucky people with high-end TV sets that supports both 100Hz and some "high-definition" algorythams (like PixelPlus on Philips, or BlackPixel DRC100 on Sony...) could see the pic with minimised shimmering.
Of course, one would also need an decent RGB cable (scart, or component in US).
As for days to come, I'll do my best to record new video in 16:9 mode of Nurb, some NY comparation vid and Capri driving vid. Calisto is working on finding some compressor that would low-down the video-size, but still maintain the high-resolution and sound quality. Guess we'll finish it in day after tommorow.