AFAIK Yellow x40's were just that; in the UK you could even get one as 1.6 petrol...
They're certainly nothing special...
AND it's a series one, so has the dial in between the vents to let cold air in, window switches down low and small side marker lights. I also think there were some other changes re the suspension between the series 1 and series 2 cars. The UK guys would know more.
Back seat will be like sitting on a piece of wood because it's got the inbuilt boosters.
Wheels definitely aren't factory.
Hope that helps.