I've used both the Springer Precison Trigger bars and the Powder river Precision Safety levers on two XD .45 with great results. The Springer trigger bar requires careful lapping to adjust it while Powder River is now supposedly making a drop-in triger bar limit/stop piece that works well with their safety lever. I'm not a big fan of Powder River's original drill-and-tap set screw method for trigger bar adjustment on the .45s. The drop-in limit device solves this problem but I have yet to use one.
If you dont want to do the work yourself, wither source will work on your gun for you. For this last option I'd suggest Springer...top nothc work and good people.
Cheers,
Jorge