If you are wanting to shed some weight just for dropping weight, look at bars, stem, seat post, wheels, crank and brake calipers.
If you are wanting to shed weight AND have actual benefit look into wheels, light tubes, lighter tires.
$100 for 150g is a big weight savings and a good $/weight ratio. Once you replace most of the larger weight items you end up dropping $50-$200 (some people maybe more) for 10-20g.
Your Thomson X2 stem is strong and some people really like the looks of it, but it is an anchor weight! If wanting a light weight weenie approved stem, look at 110g or less. Your bars are also fairly heavy. Weight weenie approved bars are sub 200g. Your brake calipers if I'm not mistaken are very heavy as well (I don't know much about tektro but I know they have a couple good sets and the rest are pretty entry level). Faf and near/planet x are some good options for light weight calipers that are fairly inexpensive for calipers.
Hope that helps