Re: GT3 weight question.
With standard (not carbon) seats and no rollcage, and my guess is that the standard Euro-spec car does come in pretty close to the stated weight, roadworthy but with no fuel in:
Sport Auto in Germany weighed a fully fuelled (90 litres), PCCB, bucket seat, PCM, SC, full leather and xenon equipped car at 1440kg. With the various additions and subtractions, that comes out at around 1395-1400 for the standard empty fuel tank car.