I'm running the Thompson Elite X2 on my Soma with the shim. The thing is, the shim is a bit too tall for their newer stems (X2 and X4), since it wasn't designed for them. You'll either have to shave it down a bit, run a spacer above the stem, or try another shim.

When I emailed them directly about it, they apologized and told me to make sure the trimmed shim was burr-free, or just to try the Problem Solvers shim.

PS, there's a crapload of Cinelli Alters up on Ebay now. Probably the coolest 1" stem ever made, if you can handle the steep drop.