Thomson’s neither especially light nor very strong ime- bent my seatpost in a nothing incident, it wasn’t a bad weight but it wasn’t very strong. Cracked my stem faceplate, was annoying as their response was more or less “Yeah it’s perfectly normal for that to happen”. Hasn’t happened to my Pro or KCNC stems, which cost less than half as much and have had probably 5 times as much use, and are I think lighter to boot.
Bars- maybe check out RSP’s Ego DH carbon, I don’t want to swear by strong as I’ve only had mine 6 months or so but it’s rated for DH use and certainly not fragile, it’s a reasonable weight (200g for the 760mm flat, slightly more for the 780mm riser, nice shape, and costs about £50. Shiny finish which is a wee bit offputting but still, very good stuff for the money. By no means the lightest, but practical, properly wide, and good everyday kit.