You aren't going to shed that much really are you?
By all means try to justify* them by needing a shorter/longer/higher rise stem, inline/layback post, wider/higher/lower rise bars to tune/play about with ride position, but really unless you are building from new or broke the last set you aren't really going to get much of a difference out of swapping them
*This tends to be my approach anyway
It may be that you can loose the most grams/£, but none of them will have a dramatic effect on your bikes handling as they're all 'static' weight. They don't do a lot
Wheels are probably the best place to ditch weight as weight ditched in rotating wheels multiplied by 3 is equivalent to weight lost elsewhere (apparantly?)
£200 probably isn't going to ditch the most weight from your current wheels compared to spending £3-500+ and get something lighter still.
Though you could get something pretty good for £200 though. Something handbuilt using eg Mavic XC717 Discs or One of the Stans Tubeless rims going for light rims, not worrying about heavier hubs (have less effect, being in the middle)
Look at your tyres and tubes and consider if you could loose some weight there. Tubeless should loose the most. You can make most 'conventional' tyres/rims tubeless with the correct conversion kit, but will weigh more than dedicated tubeless tyres/rims