I'm looking to get a carbon wrapped metal version of the ITM bar, stem and seat post rather than the full carbon options is it worth it other than the cosmetic advantage.
I'd say cosmetic advantage only. In fact if there is no weight advantage between a carbon and aluminium component such as 'bars and stem I'd be happy to go with aluminium… maybe a titanium seatpost - if you are going to be exposing a lot of it… mind you, there might be no price advantage on that.
i'd get an aluminium stem, because they deal better with the twisting forces you put through them, and a set of carbon bars, because they're more vertically compliant and give a comfier ride. save the money on the stem - there's not much reason to spend more than about £25 imho - and splash out on the bars. that's where you'll feel the difference.
Thanks for your valued comments,
with the comments above, I have had experience of a carbon wrapped seatpost, and it was not great. The carbon wrap is very thin, and is very easily distorted when clamping it in the seat-tube. You don't get any benefits, but do get the frailties of both due to the thinness of the material used.
For the most part carbon stems seem to be heavier than the equivalent ali ones, and are more flexible.
I'd go for a full carbon seatpost and bars and a good alloy stem.