I really like the blue colour on a Z4.
Especially with the bright leather, this is a very elegant look.
The colour of the wheels also fit to the blue car colour.
To enhance the overall look I would paint the silver parts (kidneys and roll bars) in a darker silver/ grey.
In this case there would still be the nice contrast to the dark blue and it would fit better to the rim colour.
The turn signals I would replace by the LCI ones and paint them in car colour.
The silver air intakes in the front I would change against the 4cyl black version (12 €/ pair at BMW). The bars next to the outer air intakes I would paint in car colour. Sample (my former N-front):
The eye lids I'd remove. In my opinion, the sporty CF doesn't fit to the elegant blue.