Amen to Thomson.
Thomson X4 4-bolt 0° or 10° MTB stem is the way to go. I'd shy away from the X2 road stem. It uses 2 bolts to fasten. Fine for most people, but if you have a strong standing start, you might break it. I did mine. I got a new faceplate no questions asked from Thomson at no charge.
The X4 will also work with Nitto 25.4 bars if you use a 25.4 to 31.8 shim spacer. I've done this with great success. Very fiddly to get installed, but solid as a rock after.
Here is one of my builds using Thomson. I used Thomson on very bike that would accept it. The only bikes that wouldn't were the Felt TK1/FRD and the LOOK. I liked the Thomson so much, I contemplated installing a standard fork just so I could use a Thomson.
Oh, and as you can see, their seatposts were tops as well.
I used their seatpost collars to make this: The unslippable seapost on the frame I designed. I asked for an extended seat tube where the seatpost collar sits. This way, I could affix double Thomson seatpost collars. Never budged 1mm.
Thomson stems and seatposts on both bikes.
About Thomson: They are an aerospace engineering company...that makes bike bits on the side for fun:
https://www.lhthomson.com/our-company/history/
That's why the quality is so high.